Authorities say Gibson was inside of her grandmother's house when someone outside walked up to the home in the 7400-block of South Sangamon and opened fire Sunday, killing the girl and wounding two others.
"She was sweet. She loved to play. She loved to come and be with me," said the victim's grandmother Christine Collins.
Gibson's family says she was excited and couldn't wait to start Libby Elementary Monday. Relatives say she had talked about it the day before.
" She wanted to get her hair done, and oh my God, she was just saying she was frantic to go to school," said cousin Lakesha Williams.
Arianna was sleeping on the couch inside of the house at the time of the shooting. She'd spent the night after a block party Saturday. Other relatives were also sleeping over when the gunman began firing into the window of the home. Arianna was hit twice and died.
"Everyone woke up. I was just throwing kids into the bathroom, and that's when I realized my little niece was shot and my daughter was shot because she kept saying she was hot," aunt Linda Chatman said.
Arianna's cousing, Stacy Jones, was wounded in the shooting, along with a 17-year-old boy. Both are expected to recover.
"You hear it all the time in the news, but you never think it comes to your family," said the victim's uncle, Jimmie Williams.
Arianna Gibson's family has established an account in her name at the TCF Bank at 87 W. 87th St. to help pay for her funeral costs. Donations can be made by calling 800-823-5363.
Chicago police said they did not have anyone in custody Monday morning and they are still investigating the motive. Some family members say they believe the shooting temmed from a dispute in the neighborhood that did not involve the child, but the information is vague.
