First, how can you be sure that you wouldn’t have learned the same material on your own had you not been “forced” to learn it in school? Most likely, you think you wouldn’t have learned it otherwise because (a) you acquired a distaste for the subject as you were learning it, leading you to believe that, had you had a choice, you would have rejected it; and (b) when you did learn it, you learned it outside of any meaningful context, thus suggesting that, had it not been imposed upon you, you never would have known about it in the first place.
This doesn’t stand up to scrutiny. Most of the things you do know and learned outside of school weren’t imposed upon you (and even if they were, they certainly weren’t introduced in the same way). You saw older children playing ball and thought, “Ooh, that looks like fun; can I play?” Or you saw a parent cooking, playing an instrument, reading and writing (not to mention walking and talking). Your dad loved learning about the Civil War and took you on weekend trips to Gettsyburg and Antietam, or the family visited Monticello and Mount Vernon, where you voluntarily took in information about their great thinkers/inventors and the world they inhabited. What a great introduction to the significance of Watergate was the movie All the President’s Men! And how many astronomers got their start by watching Star Trek or reading Isaac Asimov or Michael Crichton?
At the same time, look at all the things you weren’t required to learn—because they weren’t seen as part of the Core Curriculum of their day—that you later had to learn in order to do your work effectively? Or similarly, those current interests of yours (poetry, opera, history, puzzles, or what have you) that, if they were even covered in school, were addressed in such a way that you have since developed your passion for them in spite of your schooling. (The former Poet Laureate of the United States, Billy Collins, said, “High school is where poetry goes to die.”)
The bottom line is, no one knows ahead of time what will serve them best in the future, other than the most basic level of the three Rs, and even those are debatable in certain circumstances. What matters most are your motivation and your ability to find out what you need to know in a timely fashion. The process of discovery is infinitely more important than the value of mere regurgitation.