I was that kid in school too. I made my own go cart ripping off the plans from a cart a neighbor had when I was 8. By the time I was 12 I had built my own drag truck from the scrap/parts bin of dad's drag car.
When I took shop in high school my teacher asked me why I was in there. I already knew how to weld, use a torch, a mill, and a lathe. He was busy teaching everybody else and had me building a tool bed for his truck.