"What a ridiculous system."
What appears ridiculous is that you have failed to establish parental authority and instead have allowed a 12 year old child to make decisions certainly not in her best interests.
I agree with Lynn - it is up to you to put her in the car and drive her to school.
I suggest that you get the child and yourself into family counseling. That she refuses to recognize or obey authority and you have allowed her to gain the upper hand possibly signifies a deeper problem.