That was uncalled for and really unprofessional. Take a deep breath. I don't see any positive outcome from pursuing this with your principal. I would let it drop. Especially as you know you have lots of misunderstandings to deal with at school ahead.
You are a great mom but you don't have to be a perfect, above reproach parent. The principal's opinion of you will most likely become worse if you don't let some things like this go. You don't answer to him about your parenting. He was out of line to advise you like this. But responding to his unprofessionalism here has the potential to make you look obsessive and unbalanced. I'd walk away from this fight.
Sorry you had such a bad experience today.
