I'll agree on the first timer bias, VC's are probably less likely to invest in new entrepreneurs because the don't have a well known team and VC contacts. That's their prerogative though, it probably comes down to their appetite for risk.<p>Don't agree with the young part though, I've seen VC's say they prefer to fund younger founders.
I think if you look into the history of the people on that list, they are actually not first timers, even though they are very young.
For instance, Bill Gates and Mark Zuckerberg had built small businesses (programming consulting I believe) before they created Microsoft & Facebook.
I'm not sure of the others. Anybody know?