My daughter started going off the rails at 13, so you have had a couple more years of grace than me, she lost her virginity at 13, you name it shes done it, but ive stood by her through it all, not that ive wanted too, i too have felt like closing the door and changing the locks but i didnt and now shes 20 and has a 6 month old daughter herself, i cant say shes not attitude free cos i would be lying, but shes a lot better now than she ever was, just bare with her, and listen when she needs you too there is some light at the end of the tunnel, i promise. Good luck and keep on top of it after all your the parent not her and what you say should go. x