I read the subject line and essentially the same reply popped into my head. :-)

I won't disagree that the most important thing is to enjoy life, meet people who have real problems that need solving, and to build relationships that could last a lifetime.

That said, I spent a lot of time on the computer when I was 17 (and 18, 19, ....). I still draw upon that experience today. Sometimes, when I solve a problem or fix a bug, it's rooted in something I did way back when I was 17.

On the other hand, I also wasted a lot of time too.

My advice is to get close to a real problem. Intern somewhere. Do it for free. Get close to real work, roll up your sleeves, and try to contribute. And have fun.