I dated someone 38 when I was 24. The gap was too big. They didn't understand anything about the internet, about millennial culture, we didn't have the same humour, didn't watch the same movies, didn't have the same pop culture references, etc. About the only thing we had to connect with was music. And they were ready for kids, I wasn't.

I think big age gaps like that are problematic, and I don't care what anyone says. But people need to figure these things out on their own, so I don't really have a problem with seeing people with big age gaps dating, provided they be realistic and understanding with one another (ie, the older man doesn't pressure an 18yo to have babies just because he's getting old).