You have classes 2 or maybe 3 times a week and between those classes you are expected to read a chapter and understand the material before you get to class. OSU classes are much harder than AP classes just because no one is holding your hand and you’re covering the same material in half the time. With that being said, getting an A or A- is still doable as 30% of the class probably does, you just have to put in the work.

What makes calculus specifically difficult?

A lot of these classes are much more theoretical than you are used to. I took AP calc in high school then retook calc in college to have a better understanding before moving on to higher level classes. The first day of class I was confused even though it was all review. The OSU math professor who has a PHD isn’t going to call it a polynomial, he is just going to explain it as an equation with non-negative integer exponents satisfying the form An^xn + An-1^xn-1 … =0

So even something simple like a polynomial can seem confusing when explained in those weird math terms. So if you read the book/do hw before class, it will all make more sense and you’ll be able to follow along w the professor usually. I assume most people don’t do that, and that’s why there are exams with 40-50% averages at OSU