When I was younger I never understood the old saw about mathematicians doing their best work in their 20s, or other similar observations .... I thought it was s

When I was younger I never understood the old saw about mathematicians doing their best work in their 20s, or other similar observations .... I thought it was strange, since being older means you had more time to get more experience. Now after experiencing the pandemic... I suspect a small part of the reason for things like this maybe is they younger you are, the less chance you've had the misfortune to experience some infection or another that left you with some mild mental impairment -- including perhaps impairments so small that no individual would notice it in themselves, but in the statistical aggregate, it has an impact. As far as knowledge and wisdom go, older is better. But raw intelligence or processing power, or most of all, the one that really seems to impact everything -- working set size! -- maybe every year is only ever one more chance to get worse, and never to get better?