Sailed with family around age 7, but really learned (the hard way) starting about age 10 when they got me a Turnabout (11-foot kids' boat, very popular then up East). Then learned how to sail faster by getting the snot beat out of me in races.
I was lucky, my dad was a yacht broker/dealer, and at 17 I was doing the occasional delivery around New England when someone bought a boat and wanted it delivered (to someplace with no sales tax, like New Hampshire). I had taken a Power Squadrons Course at age 14, which taught me chart work and navigation.
Then my "finishing school" was racing in college, and later coaching that same team during grad school.
Did I 'teach myself'? In a way I did, but I had lots of 'role models'. And I had to get rid of some bad habits I 'taught myself'.
Now, as a grayhead, I get to teach others part-time.
Lucky guy, huh?