"At thirty, man suspects himself a fool, Knows it at forty, and reforms his plan; At fifty, chides his infamous delay, Pushes his prudent purpose to resolve, In all the magnanimity of thought; Resolves, and re-resolves, then dies the same. And why? because he thinks himself immortal, All men think all men mortal but themselves."
January 1, 1970
https://en.wikiquote.org/wiki/Mortality