I asked a hostel receptionist the dreaded question
I am a middle aged guy. I made friends with a hostel receptionist. I asked her if I would fit in as a hostel guest. She said there would be no problem. Yes most budget travellers are in college, but there are people in their 30s and 60s also staying in dorms, men and women, and they face no discrimination or suspicion from stuff or other guests. As long as the business allows you to stay there and you respect the rules, it is OK, and you can join in in crawls and activities.
I told her that most people on Reddit would say "Dude..." and that I have seen a thousand videos on social media about being an older man at hostel seen negatively and that even chatGPT advised me not to try it. She told me it's stupid to ask advice from randos on the internet. And that I should do my own thing and try it to see if I like it, and that if someone doesn't like me for who I am that's their problem.
Hope this helps.