Does an electric motor count?? I had one of those electric cars when I was about 3 years old.

Other than that, the first motorized vehicle I owned was a 1985 Toyota Celica.

 

A plastic PlaySkool bike.

Motorized by me.

 

YZ50 when I was about 8... Man I loved that thing like nothing has ever been loved before...

 

At 13, I bought a Yamaha moto 4 80cc quad from a friend for $300. It had no brakes or battery, even though it was an electric start. I had to push it and slam it in gear, 4 speed, no clutch. I sold it about 2 years later for $100 after trying to start the thing and hearing something snap inside the engine.