Exactly my experience! Can tell you how often I was on the brink of failing school/college because I wanted to derive as much as I could from first principles -

Exactly my experience! Can tell you how often I was on the brink of failing school/college because I wanted to derive as much as I could from first principles - under time pressure in an exam! I did myself no favors. I now find I learn better by being the opposite - finding a problem to solve and using math as a tool.