Hannah Bonser will appear before magistrates on Thursday morning charged with the muder of the 13-year-old girl.
Casey-Lyanne was found in Elmfield Park on Tuesday afternoon. She was lying fatally injured and was taken to hospital after a passer-by dialled 999, but later died.
South Yorkshire Police said that Bonser, of Cusworth House, Doncaster, has also been charged with two counts of possession of a bladed article.
Officers described the incident as a “random, isolated attack” and have appealed for people to come forward.
Detective Superintendent Terry Mann said that officers were trying to work out Casey-Lyanne’s movements after left her home in Rossington at around midday yesterday.
The teenager’s family had been left traumatised by the death, he added.
“They are a loving family. We have family liaison officers with the parents. It is a very, very sad case. They are very traumatised by this, as you can imagine,” he said.
John Willis was one of the first people to find the teenager in the park. His two sons saw her lying on the ground in a semi-conscious state and he went over to help.
“We got her in the recovery position. She didn’t move a lot and she didn’t speak. Her breathing was very shallow and she was very pale,” he said.
“The police arrived very promptly and took over the situation. I was very upset, it was very shocking.”
On Wednesday night, blue police tape was attached to railings and trees and a white forensic police tent was also set up just a few metres from a play area.
A local shopkeeper, Raja, said: “It is such a shock. It is really sad. You see kids playing football in the park.”