I quit thinking 45 was old by the time I finished college. At that age, I thought 60 was old.
As I get older (now 60!) the goal posts continue to move. Age 75 is now "old."
Quoting Billy Crystal from the Princess Bride:
“It just so happens that your friend here is only MOSTLY dead. There’s a big difference between mostly dead and all dead.”
https://www.youtube.com/watch?v=xbE8E1ez97M