Why couldn't the school have prepared me for that when I was 16? Why does preparation take precisely 12 years and only then I can really learn anything.
Maybe you're right. You're taking your own anecdotes as evidence that schooling is useless. If schooling and university didn't teach you not to do that then maybe it's not all it's cracked up to be.
The curricula for school and early university semesters are largely standardized, which allows me to generalize my observations as all other students had to learn roughly the same in school and university.
Is it not possible that schooling prepared you for this and enabled you to learn much more and faster?