[peapicker]

"Unf. you are mentally fittest between 20 and 30. " -- not in my case. My best work and all my patents have been in my 40s (so far, still there).

[mqsiuser]

You are underpinning my statement:

It's that experience (a lot of exposure in the area) is very important.

It doesn't invalidate that when you are young you are mentally fitter.