Why older men of over 50s only attracted to young girls of 30 and below???

Nothing like stating generalities. All men are not the same.

Can you give statistics???

I don't have a moustache, so with a sample size of two we find that all two of us are not the same.

Ok, let me help out my two fellows above.
Men over 50 are attracted to younger ladies for several reasons. First of all, younger ladies are still proud of their appearance while older ones just don't care anymore, leave along body shape. And another reason could be that men don't want to talk about menopause and migraine all day and night, lol.
I know I am getting roasted from a few but hey, that's fine, lol.

Can you? I think it's important to recognize that a person's romantic preferences are their own. While you might be focusing on one specific type of age-gap relationship, it's a much broader topic. We see men and women of all ages with partners significantly older or younger than themselves. Ultimately, if the relationship is consensual and everyone involved is a willing adult, their choices are their own business. The tendency to criticize these pairings often says more about the person judging than it does about the relationship itself

I'm thinking about growing a moustache.

It might not be necessary because you look great without it.

GULP!