The thing about this though is that age labeling is not the only thing that's going on, it's not just internal. Age labeling when done by others (recruiters, company policy, etc) is age discrimination, and can actually prevent entry into the tech industry. For a lot of people it's not that age is a number, it's that age is yet ANOTHER number, one they also can't do anything about.
The internalization is hard too, to be honest. For a lot of people going back to school or changing careers (especially in the tech industry), it can be much harder to stay motivated when others are in a completely different stage of life than you.