It's not illegal, but it's still weird, creepy and potentially harmful and no amount of lambasting about "the problematic age gap discourse" will make it not true.
I am 23. Whenever I accidentally come across nude pictures of an 18 year old (sometimes unavoidable on the internet, even when not searching for it) my immediate reaction is "ew, that is a child, I don't want to see that"
I cannot imagine what kind of disgusting freak you have to be to pursue these children into your 30s and 40s. :gulag: