At what age do men stop caring about being seen naked in the locker room?

In my gym it’s pretty obvious that older men are more comfortable with being naked in the locker room than younger guys, who - if they shower at all - are far more modest. This has been the case in pretty much every gym I’ve been to. So I am wondering at what age men basically decide they dgaf and just go balls out lol

EDIT: Wow, I did not expect so many responses or for the replies to a fairly jokey post to be so interesting. Just a few thoughts in follow-up/clarification:

1) It’s pretty clear that I’m confusing age with generation. Gen X and older grew up at a time when open showers were commonplace, military service was more common etc.

2) Team sports seem to be the common denominator irrespective of age or generation. This was true for me and seems to be the case for lots of people.

3) It looks like a lot of the fear is US based? From the Europeans who have replied at least, it doesn’t seem to be a concern?

4) Sorry if it read like I was judging older dudes (or naked dudes haha) or working out my insecurities (?!?). Not at all my intention. I played team sports most my life and my high school and frat had open showers. Being naked around other dudes doesn’t bother me at all. It’s just a pretty stark generational divide I’d noticed and wondered if others had too. The responses have been so fascinating.

5) Likewise, if you are the more private type in locker room situations, no judgment on that either. Everybody should just do what they’re comfortable with and not care what the guy next to you is or isn’t doing, is my philosophy!