Legal Question in Criminal Law in California

It isn't a crime for an 18-year-old date a 17-year-old unless they have sexual contact (which is not limited to intercourse). Unless your mother has pretty persuasive evidence that you and your partner have been sexually active, it's unlikely she could convince the authorities to take any action.

If you and your partner are sexually active, you should probably cool it until you turn 18. Your partner could get into a lifetime of trouble if your mother catches the two of you in the act or finds other strong evidence.

Not for "dating", but yes if you're having any sexual contact.. Statutory Rape sound familiar?