When I was 14, I bought a Yamaha 350 with my lawn mowing and paper route money. I don't remember what year model it was, but it was the year before they came out with the RD 350. Before it was over I had put expansion chambers and had the heads milled, it was a Honda 750 slayer for a 1/4 mile. After that I was looking at it's tail lights.
The first one I road was a Maverick 50. Mom made sure I new I didn't own it. My first motorcycle was a 1974 Honda CL 175 that I used on a paper route when I was 13-15 years old.