When I was 11 or 12 a boy scout buddy of mine invited me to his relatives farm in rural Kentucky where they had a Yamaha YZ50. They let me ride the YZ50 and that was it - it was a natural extension of riding a bicycle. I coveted that little bike.
I later mowed grass and saved up enough to buy a Suzuki TS125 (but really wanted at RM125) for off road riding. Never wrecked it, but put a dent or two in the bike. Finally sold it to buy a MG Midget - also from my scouting buddy's influences.
Stopped riding after getting my drivers license until I bought my '78 R80/7 in 1989. After getting the R80, I took the MSF safety course which opened my eyes to the knuckle head factor - which today has been amplified by cell and smart phones. While I primarily ride on the road I prefer off-road, mostly because of the knuckle head factor but also the scenery is better.