I think that's a bit too simplistic, unless someone can testify that the 20 years 20 t0 40 feel as long as 40 years, 40 to 80.

Here's an interesting graph and discussion on reddit: https://www.reddit.com/r/dataisbeautiful/comments/1e18fmz/pe...

Still looking if anyone has a study of (life/long-term) time perception w/ graph(s).