Joel Smith is on trial for the murder of Toni-Ann Byfield and Bertram Byfield, the man she knew as her father, in north-west London, in 2003.
Toni-Ann was excited about going to a new school
The seven-year-old has been described as a "bright, fun-loving girl", by the court prosecution.
She was shot in the back after a shopping spree with her father to buy a uniform for her new school.
The court heard how she had not stopped talking about going, so excited was she at the thought of making new friends.
Toni-Ann was due to start at her new school the following Monday after her death, just after midnight on Sunday 14 September.
She also spoke a lot about Jamaica, where she had been born and lived with Mr Byfield's ex-wife until 2000, when she arrived in England.
The jury in Mr Smith's trial has been told Mr Smith shot her to eliminate her as a witness to her father's murder. He denies murder.
Prosecutor Richard Horwell told the court the little girl was "much loved by those looking after her."
She had been in the care of Birmingham Social Services and living with a foster family in Birmingham when she died, but had been allowed to stay with a girlfriend of Byfield's.
On the night they were killed, both Toni-Ann and Mr Byfield returned to his bedsit in a hostel for ex-offenders.
He was a drug dealer who sold crack cocaine to other dealers as well as addicts.
It was at the bedsit in Harlesden that the pair were shot dead by four rounds discharged from a 9mm self-loading, semi-automatic handgun, said Mr Horwell.
One shot had been fired through the door, travelling through the back of a sink.
The fourth shot, fired from inside the room in the direction of the door, struck Toni-Ann.
Roselyn Richards, Toni-Ann's mother, laid flowers where she died
"It passed through her tiny body and was later recovered from the carpet," said Mr Horwell.
The prosecutor said Toni-Ann's death had "shocked the nation"
He said: "No human being, no matter how cold or calculating, can shoot a seven year old through the back and not feel some remorse after the event.
"The cause of the notoriety was the young age of one of the victims.
"She had been shot in the back by her father's murderer and she was seven years of age - a terrible loss of a young life.
"It was this element of this tragedy that led - compelled - previous friends or acquaintances of this defendant to eventually come forward and to identify him as the gunman."
The trial continues.