It has not been easy combining an intensive regime of studying while sharing cramped accommodation with fellow trainees.
The 19-year-old is also a teenage mother. She has had to cope with being separated from her one-year-old son Kyle, who is being looked after by her parents at home in a village near the border town of Lethem, more than 500km away. "I miss him real bad," she says. "He was nine months old when I left and since then I have not seen him." But she is determined to complete her studies in a month's time, so she can use her nursing skills in her home community.
Maria is one of the lucky ones. The prospects for many other young mothers - who account for around one-fifth of all babies born in Guyana - are not so bright. With much stigma still surrounding teenage pregnancy - especially in rural communities - most will drop out of school, their education at an abrupt end.
Maria says it was a shock when she found out she was pregnant at the age of 17, and she had expected to be told she would have to leave school. But thanks to the support of her family and head teacher, she was able to complete her exams just two months after giving birth.
"Some people didn't like how the headmistress kept me in school, while I was pregnant, but she told me that in later days it would benefit me," Maria says. "If I hadn't gone back to school after I had my child I would have never come here to do my nursing training."
Guyana, the only English-speaking country in South America, is part of the Caribbean region. The former British colony has a population of just 750,000 with the majority - 90 per cent - living along the coastal area. While the country is rich in ecology - ranging from vast expanses of untouched tropical rainforest to savannah teeming with rare birds and mammals - it struggles economically.
A high rate of teenage pregnancies is just one of the challenging issues around young people in Guyana. Suicide is the leading cause of death among 15-24 year olds. Male aggression, violence and harassment of girls and women is often perceived as normal and acceptable, while corporal punishment is still permitted in schools. Reports on cases of sexual abuse of children appear almost every day in newspapers.
According to a survey carried out in 2010 of 13 to 15-year-old schoolchildren in Guyana, around 41 per cent of boys and 18 per cent of girls said they had been sexually active. Of those, three-quarters of boys and just over half of girls (57 per cent) had sex before the age of 14.
Economic migration also has an impact. Young people frequently stay behind with friends or family if their parents leave Guyana in search of better prospects - they are known as "barrel children". Some will be reunited - but with many parents working abroad illegally, the main source of contact will often be reduced to goods sent back home in a cardboard "barrel".
In rural communities the challenges are even greater. The concept of adolescence is largely unrecognised, so once a child reaches sexual maturity they are considered to be adults. Boys are often encouraged by their families to drop out of school early in their teenage years to earn a living in mining or agricultural jobs.
Some of the most remote villages are in region nine - one of the 10 government administrative areas of the country. Acting education officer for region nine, Marilyn Joseph, describes a culture where communities are often reluctant to get authorities involved in issues such as abuse and teenage pregnancy. "When you try to help, they feel ashamed, so prefer to keep it quiet," she says.
The challenges are compounded by the difficulties in travelling around the hinterlands, which often involves negotiating huge distances on rutted dirt track roads. "We only have one welfare officer and it is hard," Joseph says. "For example sometimes we carry out truancy campaigns - but by the time you reach one location, the news that someone is coming to check on attendance has already reached the people, so it is not as effective."
Trying to tackle the problems facing Guyana's youth, which arise from a complex mix of economic circumstances and ingrained cultural attitudes, is not easy.
But with the support of children's charity Unicef, a new subject has been implemented in nursery, primary and secondary schools to try to address these issues. The Health and Family Life Education (HFLE) classes attempt to provide pupils with life-skills - ranging from education on safe sex and HIV prevention to improved self-esteem and confidence. It was introduced initially by being "infused" into other subjects: pupils in a maths class, for example, might discuss what to do if a shopkeeper hands back too much change - addressing both arithmetic and issues around honesty.
A more structured programme with timetabled classes was then developed, to include subjects ranging from sexual abuse to dealing with peer pressure and the risks of drugs and drinking.
Jewell Crosse, youth and adolescent development officer with Unicef Guyana, says: "In Guyana, we have similar issues which are across the Caribbean, such as the migration of parents to other countries. We have issues of teenage pregnancies, children dropping out of schools, abuse, violence and so on.
"We have seen that HFLE has started to address these issues. It is helping children to gain skills like decision-making, which should help them to make good choices, which will also be long lasting."
At North Georgetown Secondary School, 14-year-old Ashly Khan reels off a long list of topics that have been covered in her HFLE classes - such as positive thinking, HIV, sexually transmitted diseases, teenage pregnancy, abuse and domestic violence.
The lessons have also helped her deal with the emotions of growing up. "I am usually emotional and when people talk to me in a bad way I don't really say anything," she says. "But if they do that for the whole year, at the end of the year I used to want to shout and say stop it and to cry about it.
"Now I usually just call those people and talk to them in a calm way and tell them the reasons I don't like it. They either say sorry or explain why they were doing it."
Her classmate Tyron Rhamanohar, also 14, believes the classes have been useful in helping him not to react angrily to situations. "When someone tells you something and you get vexed and ready to fight, you can calm yourself down, learn how to solve it and not put yourself into jeopardy," he says.
Tyron says he has never experienced the gang culture which is common in Guyana, but he would be confident of his ability to refuse to join in.
"I have heard from other students that to join a gang you have to maybe do bad things - drinking or smoking or go to pick some pockets, to prove you are bad," he says. "You learn how to refuse, how not to get into an argument with that person and to keep away from alcohol and drugs.
"You can refuse it because you have learned how to say no and express yourself."
He adds: "In my life it has benefited me a lot as I know how to handle myself, know how to stay out of fights. I hope that these lessons could keep going on to the future generations - children have learned from it and I hope it can continue like that."
And while the sun-drenched streets of Georgetown, which teem with minibuses, cars and horse-drawn carts, seem a far cry from Scotland, the worries of parents here are not so different.
At Tyron's grandmother's house, his mother Sharmila, 41, voices concerns about the impact of mobile phones and internet access on today's generation of children.
"The children are so much wiser now," she says. "It is not like in my time, we were more old-fashioned. Now the children know so much more, they are exposed to everything because of television, movies, mobile phones and everything else.
"You're not around all the time to monitor them, to know what they are looking at."
Back in Region nine, Yvette Archer, head of St Ignatius Secondary School near Lethem, believes HFLE classes have contributed to an improvement in pupils' school attendance.
"I can see students attending more regularly - we had a lot of students drop out previously particularly between the ages of 13 to 15," she says. "I would like to think the improvement is related to a newer perception of life, some of the skills the children are learning in how to cope with home issues and whatever is happening to them. They are seeing how completing their schooling can be a positive for them."
Archer, who has been head of the school for five years, is impressive in her determination for her pupils not to fail: she is the head teacher who was determined to keep Maria in school while pregnant.
She says: "Normally what would happen is as soon as a child is pregnant, they are pulled out because of the embarrassment and the pressure and every other thing.
"I said, 'I know it is going to be hard, but I need to change the statistics on it - we will not have another teenager drop out of school because she is pregnant.' So I was happy to do that - but it was not easy."
HFLE is now in 98 out of 120 secondary schools across Guyana. Progress is being made - but there are still challenges. For example, Archer describes how she had to pause the programme for a short time due to staffing shortages.
An evaluation of HFLE in Guyana published by Unicef last year noted it has had "moderate success", but building on that in the long-term will rely on "adequate and sustained" investment.
Trying to influence the improvement of government policies might be a less visible form of aid work than providing clean water to a village - but it is just as important.
Marianne Flach, Unicef representative for Guyana, says progress is gradually being made in improving life for the country's children. She points to the example of the government setting up a child protection agency in recent years.
"Last year they received more than 2,000 complaints, and at least they tried to help those children in protecting them," she says. "But that is the tip of the iceberg - there are many cases that go unreported." n