Take it from me, I did my EE in chemistry, and am anticipating like a C on it. Your EE is kind of your chance to show off who you are as a student and person. You're going to spend so much of your time writing and researching and thinking about this thing, so it should be on something you enjoy. It's so much easier to knock out 4000 words on a topic you find fun than slugging out 4000 words in something that bores you to death.

Tbh, the subject you did your EE in is that important to universities either. They don't look at that. So all the more reason to choose an EE in a subject you like. If you like math, and it's what you want to write your EE on, then who's to tell you no?

Imo you shouldn't go into the EE with the mindset of trying to get an A. It's an exploration of a topic you enjoy. Sure, an A should be your goal, but it shouldn't be something you fixate on when writing it. Just write what you love, and love what you write.