Except that's all anecdotal. How do you measure how good someone is at programming? Have there been any studies comparing intro age to programming with future performance? Anecdotally, I know plenty of people who have been programming since elementary school who are terrible compared to someone who learned in college.

And it's not hard to guess why. Just because you've been programming for a long time, doesn't mean you were doing it correctly, or even understood what you were doing.