Well, now....not necessarily. I started working on cars with my grandfather when I was very young and actually started modifying my first mini truck 2 years before I even got my driver's permit. Couldn't even drive the damn thing.
It's funny...when most kids were just learning how to mow the lawn, I was already able to rebuild the mower motor. I started doing oil changes on my dad's truck and my mom's car when I was about 10.
I am not the only one that started very young as a LOT of my friends did as well. Then again, automotive culture is what I attached to early, so that might be why most of my friends now are mechanics or at least enthusiasts.