It's pretty damned rare for somebody to learn late in life (after 18). That's the hard ugly truth of the matter.
Yes it's true that a lot of programmers started early but please you are making the correlation == causation fallacy here. There's NO proof that starting earlier means you're better. I've met some really good programmers who started later in life because they thought they wanted to do something else, and when they found programming, it clicked, and then went crazy with it.
Time spent doesn't mean you're better after that time. Time spent trying to get better DOES mean you'll get better over time, and that has nothing to do with how early you start.
This also isn't only for programming but any profession.
Programming well is hard, but not that hard.
Also, Debian contributors aren't a really good group to take samples out of...