I don't think we'll know the answer to the age question for a little while. The number of coders has been growing over time, so the potential pool of seriously older coders (60+ for sake of argument) is already small to start with.

Anecdotally, three very different examples:

my mother (71) stopped coding in 1969

Guido van Rossum (60) is still coding

Darryl Havens (61) is Distinguished Engineer at Amazon - not per se a coding role, but definitely an engineering role