At age 5, I can remember assembling clippings about the Space Shuttle (although that was 1981, so I guess nearly 6.) I was an early reader, and I already loved computers, but I don't remember when we first got a VIC 20.
For age 15, I'm having trouble coming up with specific memories. I was the track team's best two-mile runner, which was not saying much. During my sophomore year I went to the state music competition as a soloist for the first time (by scoring well at the regional competition)--- I remember my mom driving me out to UW-Whitewater.
I was going to say that I bought my first computer, a 486 running at 33 MHz, but I remember running Windows 3, so that might have been at 16. I'm also having trouble remembering what I did that summer--- I think that it was a yard project, putting in edging; my software consulting gigs for Eaton were later.
At 25, I was still making the commute to Stanford for graduate school, but living in Concord, CA with Marissa and Tim (though we moved down to Hayward later that year.) I passed my quals sometime around that time, but probably when I was 24. David Cheriton circulated his somewhat inflammatory paper on TRIAD (our next-generation Internet architecture) which listed me as a co-author. I started working for Kealia the following January, and had my USITS paper published that March.