The girl is expected to survive.
From an article:
Riverdale police say several people are being questioned after a nine year old girl was shot in the stomach inside a home on Steeple Ridge Court Friday afternoon. Investigators say the child, who was airlifted to Children’s Healthcare of Atlanta, Egleston, was able to identify the person who fired the gun. Police say the victim was at the house, with other children and several adults, in some kind of babysitting situation, when a 19 year old female, mishandled a gun and it discharged, striking the child. Her name has not been released, and police have not named the teenager they say had the gun.
According to another article, the shooter was in possession of marijuana at the time.