I minored in math in undergrad. In about the second week or third week of each math course, I would strongly consider dropping, convinced I wasn’t clever enough to pass.
I made a B in one of those courses and an A in every other.
No matter how many math courses I took, I still had that stomach-dropping panic that I was going to fail the course the first time I didn’t immediately understand something.
I really wish I could talk myself out of this ridiculous mental habit. It does not help me learn new math, not at all.