Takes Patience

As the parent of a 12 year old tween, I have learned that it takes patience. Can someone please tell me why it is my fault as a parent (according to a 12 year old) when she PLAGIARIZES and gets caught and gets an F? Do I remove all of her friends from the component? She has already lost entertainment... I am at my wits end. I guess if anyone could answer that question, they would be rich.. Damn it is not me...