12-year-old daughter

I am having a lot of trouble with my eldest daughter. She has never, I think, come to the truth in her heart about admitting when she has made a bad choice or a mistake. She hates corrections and going to the 3 majors makes her furious. We have been implementing the TSG methods and principles since we did the 3-day parenting course a few months back. I have had major breakthroughs and success with governing myself and teaching my six younger children. We have established our family creed and vision and been practicing these. We have family meetings each week and mentor meetings for the children – half every second week. I have done parent counselling sessions with my 12-year-old when she finishes the 24 hrs loss of privileges. All the other children are striving to use their skills and we have more love, joy and peace with them.
But with my eldest, it is an entirely different story. The methods of TSG have brought to the light a lot of her hidden bad habits and faults. And she hates that. She has always wanted to be seen as a good girl, but she hasn't put much effort into actually being good. For the last week she has consistently chosen to go out of instructional control and for the last 4 days, she has not been able to start her 24 hrs because she has not chosen to be calm and follow instructions. During the period she has heaped verbal abuse and me, her mother, and on her younger sister. The verbal abuse is getting worse, more and more targeted at trying to get me to react. She hates it that I stay calm. She's miserable and stressed out and I am finding that I am getting exhausted. The verbal abuse affects me physically because I have chronic fatigue, brought on by a very stressed out childhood and my stomach cramps up after prolonged verbal abuse. I am on my knees praying for her and calling out to God for wisdom many times a day. I give her cuddles and tell her I love her and that I hope she has a good day. I know that she has run up a great emotional deficit and I'm trying to communicate love, acceptance, and forgiveness to try to heal the relationship. But I know that she cannot progress until she comes to the truth of admitting where she is wrong. It seems so simple to me, it seems like it so safe to admit mistakes and that there is plenty of teaching and role play to reinforce good choices and their consequences. She hates it that the other children earn positive consequences and accuses me of favoritism. We need help!