Me & my dads girlfriend had a fight? Who's in the wrong?

If she went over the top about you eating pizzas with knife and fork she was wrong in that. How you eat pizza is a preference, not a law. You however broke an unwritten law cy calling her a c***, and you have to apologize for that. She should apologize for yelling at you at your parents, that isn't right no matter what time of the month it is but be the bigger person and apologize for calling her a bad thing.