At 15, I bought a well-used 1971 yamaha 125 enduro in November, in Iowa. I spent many hours over that winter sitting on the bike in the basement, drilling it into my head: clutch, front brake, rear brake, shifter, throttle... When spring rolled around, my dad and I wrestled it up the stairs and out onto the driveway. It was very much a self-taught thing and I scared the bejeezus out of myself when I let the clutch out the first time. I managed to just miss a parked car, did a feet-down u-turn that took the whole street width, and drove through the front yard getting back to the driveway. I got off the bike, shaking from adrenaline, but thinking about what I had to do differently to keep the bike in some sort of control. I managed to survive being self-taught, and passed the driving test to get a motorcycle endorsement on my license on my first attempt.
After a couple of years, my dad suggested a different bike (a KZ400 that a co-worker had won in a raffle) because he was tired of hearing the two-stroke ring-a-ding-ding noise when he was trying to get to sleep and I was getting home from my part-time job. I eventually took the MSF course on that bike when I was in the service. Then came roadracing school (WERA), an RD400F, a BMW R100S, a defensive motorcycle riding course, Keith Code Superbike School, another roadracing school to get a competition license with the CRA, another roadracing school to get a competition license with the CMRA, and most recently a couple of American Supercamps and a Total Control class.
I'm still learning.