The right thing to do here would be to cut her off. Block all forms of communication and you will get over her. Its v simple really since you never met in real life. Just stay away and start talking to someone older. You will soon forget her. Shes still a child and she js v vulnerable considering what she has been through. And sexual abuse does NOT make a person more mature, it actually hinders and slows down their development. They are stuck, frozen at that age mentally and emotionally until they get the treatment they need.
"Don't ask a question if you can't handle the answer".