Dude, chill. How old is she? I'm guessing around 17/18 if she's in your school year. Most girls do that at that age anyway if not earlier on in their lives, these days it's the "thing" to do. If you love her you'd accept it because that's part of who she is, and that's the person she is. At the end of the day that is/was her choice to do, and you've got to respect that.
Anyways, I don't see a reason to close this thread at all.