I stopped by Fragbite - a CS oriented site (mostly in swedish) and they happened to have a poll going on there atm. The question was:

Did you been play CS when you were younger than 15 years old?

Yes, It started early (60%)

Yes, I'm still younger than 15 years old (15%)

No, but I know those who did (10%)

No (15%)

Out of 12410 Votes


Link to the poll is here (in swedish)