Re: Worried about my pre-teen daughter, please help.
I agree with Muzna, and also at the same time, I would start removing the posters and such from her rooms. You can tell her that you are doing it because she is now ready for namaz and cant do it with pictures in her room.
That might require you to remove pics from your rooms also (if you have them) cause she will definitely object.
I know this all sounds pretty serious and it is, but dont lose your sleep over it. It all can be taken care of slowly.