That is such a tough age. They really think they know what's best for themselves and just want to be free from the parents. My heart goes out to you.
I highly suggest attending Al-Anon meetings.
One thing I have learned is if they really want to leave they will, it doesn't matter their age or what we as parents want. The fact that she is "asking / begging" does show that somewhere within her she wants your approval and that is a good thing.
If it were me I would just keep trying to get her to see a therapist. Reinforce to her that she is loved.
It's a difficult road that you are on and I am so sorry for what you are going through but you will get through this.
((HUGS)) to you..............
