This is a testament to my parent's homeschooling, for one. It was not particularly demanding, as far as book-work goes. But we did get all kinds of education that cannot be taught out of books. I often think to myself - I know that word because Dad used it or I know about that phenomenon because we were exposed to it casually on family outings or work adventures. I finished 12th grade at 16, failing miserably at math and just wanting to finish the official school work. The reason finishing early was possible was because everything but math was well above average. Though my parents didn't have a lot of money when I was growing up, they somehow bought a library from a private school that was closing. We had a whole room, plus more, full of books, and the purchase also included a nice microscope. We also had lots and lots of tools at our disposal. My oldest (younger) brother was welding by the time he was 12 or so, and he rebuilt a bus engine under my dad's supervision when he was 14. We had access to handtools, sanders, saws, airtools, welders, etc.
What a good education I've gotten. Thanks Mom and Dad :)