Yeah, I don't get it. I'm 38m and don't find college-age girls attractive anymore. Even in terms of physical attraction, I'm more attracted to women my age. 18 just looks like a kid to me.
I'm 38 and anyone under 30 looks like a child to me by now. 28, sure, they're probably old enough despite the lack of life experience and looking a little young, but 18-year-olds still have baby fat! Gross.
If I see young people of that age group it sometimes makes me remeber of when I was that age and the fun I did/could have had. Nothing in me wants to engage with any of that at all anymore. Just happy care free memories.
A few years ago a friend had a 40th birthday and his gf arranged a night out. She took us to a night club in a university city. It was such an odd experience. We left pretty fast.