It was the day the International Olympic Committee declared that London was awarded the 2012 Games.
Bentley, an Aberdonian, was working in an office in London and meandered along to Trafalgar Square to see the announcement being beamed live.
"When I heard them announce it was London, I pretty much decided there and then that I had to go for it and that I would do anything to compete in London 2012," she says.
It all came true for the three-times British foil champion last month when she was confirmed in the Great Britain fencing team, one of two Scots (Richard Kruse will compete in the men's foil).
From a sporting pedigree – her grandfather was former Aberdeen footballer and visionary director Chris Anderson OBE – she lived in Aberdeen for the first 10 years of her life before the family moved to Norwich after her father took up a job offer.
It was there she first experienced fencing at a come-and-try session at school, progressing to her local club where she started gaining success in age-group competitions.
"My first coach, Andrew Sowerby, did a great job laying the foundations for me which my long-time coach in London, Tomek Walicki, has continued to build on to make me competitive at international level," she says. "I owe a huge debt of gratitude to Tomek as he has always supported me and has been the biggest influence on my fencing."
A silver medal at the Commonwealth Championships six years ago underlined what Bentley is capable of but she considers herself an outsider for a medal. A 13th place at the last European Championships was her best international result so in a weapon where Italian Valentina Vezzali has been dominant, winning the last three Olympic women's foil individual titles and with seven medals in all, she will need the help of a partisan support if she is to upset the normal order.
"Our strongest chance of a medal is in men's foil, but we are strong in several weapons and we have many outside chances," she says. "Hopefully, with the home crowd behind us it will help raise our performance and then who knows what might happen? In foil, the strongest countries are Italy, Russia, France and Korea. If Vezzali wins the gold medal in London, it will make her one of the most successful female Olympians in any sport. Home support is going to be huge for us. I had my personal best performance in Sheffield [at the European Championships in 2011] so I know what a difference it can make. I can't wait."
Great Britain has not won an Olympic fencing medal since 1964 in Tokyo when Bill Hoskyns won a silver but Bentley says the team have made significant strides over the past year and beaten nations such as Japan, China and Korea for the first time. Keeping cool under pressure will be the key.
"Sports psychology plays a massive role in fencing," she says, "At international level, the technical differences are tiny between the fencers, everyone can pretty much do all the moves. But it's the ability to keep calm under pressure, to keep thinking tactically and flexibly when things are getting hard and especially when everything seems against you, that is what separates the winners from the rest. You can feel quite alone on the piste. You are up there on your own, often you can't hear the coach, so you have to keep thinking clearly. It's really tough which is why I love it."
Bentley has been fortunate to concentrate on fencing full-time in the build-up to the Games with insurance company Beazley having entered into a five-year agreement with British Fencing, lessening the financial pressure on elite fencers.
"The UK Sport pathway programme, sportscotland and Beazley's support have been brilliant and I couldn't have got here today without it," she says. "Their support is huge and has given me and the rest of the team a full-time training programme with all the sport science back-up [physio, doctor, video analysis, strength coach] and enabled us to compete at all the competitions around the world and several foreign training camps too. This season we have already been training in France, Poland and Japan which is crucial for our competition preparation.
"I coach at some local London schools for some extra money but I haven't been coaching much this year as we've been away from the UK so much."