When I was 13 I had a crappy old PC that I used to take apart and fiddle with. When it bust altogether, I pretty much forgot about computers.
I reached 14, I lost my brother, and as I watched my family crumble I turned to drinking and smoking weed. Yes, at 14. I hung out with the wrong crowd, I did things I shouldn't have and I spent my school time living up what was deemed the "ideal" social life by my peers.
A year or so later I got really in to computers again. I started making web pages; I got a new (old) desktop which I tweaked up and geeked out on. I progressed from HTML and CSS to PHP (and yeah, I know that PHP has a bad rap amongst most hackers here, but I like it), spent all my time in IT at school etc. I gently progressed in to a real computer nerd.
Looking back now, I can honestly say that the time I "wasted" messing about with computers, teaching myself how to code, etc.. they were the best of my teenage years, and I have no regrets on how I spent my time. It is who I am, I enjoy doing what I do. I wouldn't change for anyone.