Well it’s weirder if you’re 30 and she’s 18 because also you’re 30 and she’s 18.
I’m not so sure. It’s weird for a 30 year old to date an 18 year old (but not illegal cause 18 = adult). But is it weirder to ask the parents of an 18 year old than it would be to ask the parents of a 30 year old? I mean 18 year olds still live under their parents roof in many cases even though they are legally an adult. 30 year olds are usual on their own so asking the parents permission is not necessary.