The first time I rode a bike was an old Honda Fat cat my buddies had, I was probably 13 or so.
Then my friend had a ttr 225 when I was 18 or so, and I rode that on trails with him. Then I bought it, traded an sks for it. Sold it after a few months as it had bad rings and burned more oil than gas and I was an idiot.
At 23 I got a Suzuki Marauder 800cc cruiser. I tooled around our local roads in my neighborhood for an hour or two, then took it on a real road. I remember driving at 45 and seeing all the stuff on the side of the road and imagining what it would do to me if I crashed.
Well I put 15k miles on that and now I have a KLR 650.
I never took the MSF, but have read Proficient Cycling and study motorcycling to become a good rider. I loved the marauder at the time, but once I got the KLR I rode it and the damn things is a pig. Crappy handling, brakes, and too low. I sold it asap.