I bought a Kawasaki KV75 mini bike from a neighbor's kid for $75 when I was in middle school. We had a twenty acre field behind our house where I essentially taught myself to ride it. A few years later I got a 1972 Honda SL70. That bike taught me how to shift with a clutch. The SL70 was a street legal enduro. My mother threw away the title and registration that came with it so I couldn't use it when I turned 16. I ended up blowing the motor and selling it. A friend had a new Suzuki RM125 that amped things up a little. After we moved I stopped riding with the exception of the rare occasion when someone would invite me out to ride. I had never ridden a street bike until about a year and a half ago.
My main transportation is a Ford F350 diesel which gets 12 to 13 mpg. A friend at work bought a Suzuki DRz 400 for commuting. He convinced me to buy a dual sport to save fuel, but since I am a bigger guy, I opted for the DR650. I bought the bike and practiced in our pasture for a week before I took the MSF course for my license. After I got the license I went out to a state forest to practice at higher speeds on the dirt roads. I basically went back to the off road that I was comfortable with before hitting the streets. After twenty years of not riding, I kick myself for all the years that I was away. I have been able to go places and explore areas I never could reach before. It has provided a much needed outlet for stress relief too.
To answer the OP's question, I am mostly self taught.