So, does anyone know if werewolves age or not, or if their aging process is slowed?

They definitely age, probably just like normal people because nobody seems to know when people are werewolves.

Judging by the Companions questline content in Skyrim, it would seem that werewolves do age. Unless of course Hircine blesses them with longer lifespans.

They definitely age, longer lifespans is a possibility, but I think unlikely, because you never hear about it and equally improtant you'd think people would notice some other people living far longer then most...

Tharsten Hear Fang lived for generations. But that's because he had the ring of Hircine which made him live longer. We still don't know if Lycanthropes age slower though.

People skilled in magic tend to live long lives because of it, so a long lifespan might not be view as abnormal. An example is that most people assume that the count of Skingrad during the time of the Oblivion Crisis even though he have a long lifespan of an entirely different reason.