I don't actually know what the "first" game I played was, but I always say it was Hot Wheels: Beat That on PS2 because it was the first game I got on my first official console.
I used to play a lot of Flash games when I was younger. I recently downloaded Flashpoint, which is one of the Flash Game preservation projects that has a pretty good selection.
I was lucky, I never got any really bad injuries as a child. The worst I can think of was when I fell off the monkey bars directly onto my back, got the wind knocked out of me and could barely walk.