Sure, but this doesn't explain why most people working in startups are in their twenties.
The data isn't for people working at startups — they only survey founders, and I think CEOs if the CEO is a non-founder.
Avg age at my company (Series A funded, 50-ish people) is >30. Founders started at 35 & 36. Now they’re not-quite-40 and 40. Your sample size may vary.
At my startup, in my late 20s, I'm one of the older employees, excluding founders & management.