When discussing women in tech, people bring up how the candidate pool mirrors the pipeline. See the recent discussion on Google. https://news.ycombinator.com/item?id=7813310

Are you arguing that women are inherently less likely to commit early?

Guys are more likely to start coding in high school or earlier, so they're the ones starting freshman year. For example, the number of women who take the AP CS test is ~18%, which is close to the % of CS degree grads who are women.

http://www.exploringcs.org/resources/cs-statistics

If you want to graduate in 4 years, you have to start your CS program freshman year. You can switch later, but you're going to have to pay for more semesters, or work harder and cram in more units. And yes, you can start coding after 22, but it's an uphill battle.