For what it's worth, I struggled with math in elementary school and especially high school -- I failed algebra I, then passed it with a D; then I failed algebra II before passing it* with a D. It wasn't until I was forced to take a business calculus class in my 20s that it started clicking, and I assure you the quality of instruction wasn't any better at the college level than it was in high school. (I did eventually graduate with honors with a math degree.)