(idiom) something is too difficult or complicated for someone to understand
A: Do you ever wonder if God is real?
B: That stuff is so over my head that I never try to think about it.
Before the Olympics, Angelina tried to learn how to speak Chinese. Unfortunately, it was over her head, and she quit after only 3 weeks.
A: What do you think of the new professor?
B: His teaching style is way over my head. I can’t understand what he’s talking about.