What an interesting and strange childhood you must have had to be writing games in Pascal before you heard about cosine. Either your schooling was great or terrible!
Maybe it's not the schooling. I went through a similar experience, because I started programming when I was 7 years old. By the time I had learned enough to want to try to make a game, I had taught myself Turbo Pascal, but I still wasn't of an age to learn trigonometry in school.
The first sentence is the same for me but to just pick up programming when you're 11 or 12 by yourself seems crazy! I'm sure you had a mentor or an older friend or some adult that at least exposed you to the concept.
I remember vaguely a course on Basic on Amigas. But other than that, I didn't really have mentors or peers. I believe I learnt QBasic from a book, later Turbo Pascal from another book and assembly from yet another.