The difficulty of calculus depends directly on how intuitive you find calculus. I don't know whether it's a question of "mathy".

With calculus, I think I was completely confused for about one month, figured it out, and then proceeded to sleep through the rest of the year while getting a 100%.

With me, either I understand the theoretical underpinnings or I don't. For instance, I never unlocked differential equations, so I have virtually zero ability in that area.