Yes and no. If you look at the comics Superman has more or less show that he can and will age but very slowly. Kingdom Come is a good example because while Diana looks basically the same Superman's features are weathered and has the grey/white temples in his hair.
as much as i am a fan of Kingdom Come, it is a bad example to use as a basis for Kal-El's aging process. truthfully speaking, Kal-El's invulnerability comes from our yellow sun, so if you follow it logically, the only time Kal-El would age is when our sun starts turning red (or during those times that he is in an environment with no yellow sun). i know what post crisis writers did with trying to depower him and all the BS, but since they're sticking to the yellow sun invulnerability canon as well it kinda makes their stories contradictory (on a side note: Superman's powers and abilities has been revamped so often since post crisis its as if nothing changed

)
oh and fyi, i remember reading an interview about Alex Ross on why he made Superman greying, and his reason was more figurative that literal, he wanted to portray that Superman has "lived life" and wizened from the last time he was active.
Ultraman Nexus said:
Based on that I don't think it would be as big a deal in casting because being agressively youthful is not something that's built into the concept the way it is for Wonder Woman who is created by magic or Wally who archetypically is supposed to be a young guy. If it's Barry however then I kind of wonder why casting young is such a priority unless their "Barry" is a blending of the characters.
guess you dont know much about WW huh?
WW's aging process has been even less consistent than Superman. there has been numerous discussions on her mortality/ immortality, but for all her history one things for sure: she does age. she can get hurt and she can get killed. she's essentially human but with special gifts from the gods (invulnerability, flight, strength, wisdom et al), which makes her almost equal to Superman. contrary to what you read from random articles on the internet, she is not an ageless goddes that never changes (she's not even a goddess anymore!).
as to how fast WW ages its still up for debate. during Pre-Crisis the canon was that whenever she's not on Paradise Island she begins to age. in Post-Crisis it was never made clear just how fast she ages when she's in Man's World, however there are several stories that mentions that she doesnt stay ageless.
hope that clears things up for y'all
