Alyssa Bustamante is accused of killing Elizabeth Olten by strangling the girl, cutting her throat and stabbing her on Oct. 21.
Bustamante also is charged with armed criminal action for allegedly using a knife in the attack.
The indictment Wednesday came hours after a judge ruled Bustamante should stand trial as an adult. She is being held without bond in Cole County jail.
If convicted of first-degree murder, Bustamante could be sentenced to life in prison.