Friends said Shereka Marsh was sociable, good at sport and had wanted to study business.
Police were called to the shooting at a house in Hackney, east London, shortly before 4pm on Saturday. The London Ambulance Service and Air Ambulance attended but the 15-year-old girl was pronounced dead at the scene. Two 16-year-old boys and a 15-year-old boy were arrested nearby and taken to an east London police station where they remain in custody, a Scotland Yard spokesman said. He added that a gun was recovered from the house.
Mourners visited the scene yesterday to lay flowers and leave messages of condolence.
Chainelle Jennings, 16, a friend and schoolmate of the victim for five years, was among a group of eight of the girl's friends who gathered opposite the house where the incident happened. "She was a nice bubbly girl and she loved to party, loved shopping. She was just like the kind of girl that you would have to fall in love with," she said.
"She liked PE. Her favourite subject was history. She was good at sports. She wanted to study business.
"She lived with her mum, her dad was in Jamaica. They just had each other, just them two and they lived together. She cherished her mum. Her mum was very protective."
Chainelle said she had heard Shereka was accidentally shot in the neck and bled to death.
A Metropolitan Police spokesman said: "Officers believe they know the identity of the deceased and have begun informing family, however they await formal identification. Detectives from the Met's Homicide and Major Crime Command are investigating."
A post-mortem took place yesterday, and the girl's body is not expected to be formally identified until today.
Police have been standing guard outside the terraced house where the shooting happened.
The street, which backs on to Wick Woodland, remains closed to allow detectives to carry out their inquiries.
It is just yards from the site of the Olympic media centre and minutes from the Olympic Park.