Before we try conditionals, I think we could do with some simple reported speech.
This is the context I inferred from your question (please correct me if I'm wrong):
My mother went to school and said (to the teacher): "Until you
apologize, my daughter won't attend your classes."
You know, my mother went to school and told my teacher that until she
apologized, I wouldn't attend her classes.
I suppose because the sentence is part of an ongoing narrative, it would be enough to just use reported speech and its tenses rule.
But if we isolate your target sentence, you can employ your past conditional:
My mother went to school and talked to my teacher. If she hadn't
apologized, I wouldn't have attended her classes.