I don't remember exactly how old I was, but it was in the 6 - 8 age range. That's about when my dad gave me and my brothers our first computers. We had them all lined up on this long desk that had three sections to it, and my dad installed three keyboard drawers. My older brother (12 or 13 at the time) had an SE/30, I had an SE, and my little brother (4 or 5) had a Plus. That's the way it was for a while. My older brothers computer kicked the **** out of mine and my younger brothers, as some of you know. 😀
At some point, we all got upgraded to SE/30s, and I had the most beefed out setup. I had a 1.2GB hard drive, 32mb of ram, Mac OS 7.5.5, an external zip drive, Apple CD Rom drive, PLP Printer, Scanner, and even an additional external floppy drive I think. I did everything on that computer. I created art, animated movies, drawings, games, etc. I learned how to crash it, and then how to fix it. It was awesome. It wasn't until I was about 14 years old that I was upgraded to a PowerMac G4 "Yikes" 350mhz tower, and it wasn't until I was almost 16 that I got internet on my own computer. I'm happy about that because it caused all my explorations on the Mac as a little kid to be entirely creative-based, with no distractions from the internet.
Anyways, I would almost always accidentally crash whatever machine i'd get my hands on, because I would experiment with everything, so when I was younger i'd spend a lot of time biting my fingernails while watching the screen of some Mac, hoping that the start-up disk I put in will boot up the computer.
I could go on and on about my fond memories of teaching myself the Mac as a kid. 🙂