It didn't mess up my life, but when I was in high school the conventional wisdom was that being well rounded helped you get into good colleges. I spent a lot of time playing team sports and the saxophone; neither of those are hobbies of mine today. I wish I had spent some of that time doing something that would still be relevant to me today, like programming (there are a LOT of successful founders that started programming in their early teens; I didn't start until college).
I sort of value well-roundedness even into adult life. Sure, I didn't morph into a programming genius that spits out code in his sleep, but I do think time spent playing sports and hanging around with friends sort of saved me from being less introverted and shy than I could have been.
There are times that I envy young, successful founders running companies worth millions, laser-focused on their goals from childhood to adulthood, but then again I sort of do a double-take and think: They couldn't have been this awesome without missing some important aspects (to me anyway) of life. Aspects like falling in love, winning a girl's heart, getting into trouble, exploring new places, learning a musical instrument and hanging out with people with different interests and intelligence (street smart or artsy types). I mean, you can only be young once (and of course, your hormones would only be THIS active once).
Most of this will be considered a massive waste of time for some people (I certainly considered all my years spent playing games a waste. Damnit.). Still moderation is key.
Oh, I didn't start seriously programming until I went to college, and life didn't turn out so bad. (Still, no million-dollar company under my name though =()
That's a good one. What colleges are really looking for is:
1. Expertise in something the college values. For Ivy Leagues and the like, that's usually something academic or artistic. For military academies, that's leadership. Athletics for some schools, though you've gotta be world class or clearly heading there.
2. Good grades (unless you're going for a sports scholarship)
3. A few interesting extra-curriculars to show you can 'multitask' and aren't completely 1 dimensional.
But many parents seem to over-emphasize #3 to the detriment of #1 and #2. If you take them seriously you'll find yourself a jack of many trades, master of none. But it's the masters of particular trades/crafts/domains/knowledge these days that are irreplaceable, un-interchangeable, and who make the advances that push the human race forward, not the jacks.
And the ability to truly master something is difficult, a skill in and of itself. Those who develop that skill early in life will have a significant advantage over those who don't.
So if you find yourself trying to do all three and struggling to keep all those balls in the air, don't be afraid to drop #3. It's expendable.
Starting early is not a requisite for success. I started programming when I was 19 or 20 (not that I'm necessarily a successful founder but I have found some measure of success during my IT career).
Your knowledge in various domains likely helps you in ways that aren't immediately apparent. (Team sports, for example, are great for health but also for social skills.)
The big advantage is that you can get to your mid-20s with 10 years of experience and lots of practice, and then be mentally ready without having the commitments of a house, wife, kids, mortgage, etc. tying you down. You can get those same advantages by delaying dating & childbirth until later in life, although then you sacrifice in that your kids may never know their grandparents.
When it comes to software, I don't think starting age matters that much, except perhaps on the margins. The field changes too quickly for amateur technical experience from 10+ years ago to have much of an impact on quality. The kind of experience that ages well is the kind that you can't easily get as a teenager with a Linux install.
Also, every time I interview someone, I ask them how they got into programming. So far, there's been no strong correlation between quality and years of experience. The people who started programming in elementary school are just as likely to be crappy as those who didn't start until college.
The strongest predictor I've seen for engineer quality is college GPA. People who work hard and get things done also tend to get good grades.
