If one can convince himself such thing, that means a serious mental illnes, kind of im sure i am free of, thanks god :D Please refrain of imputing this personally, i was sure this is general discussion.
As a matter of facts, there is a similar thing with older (especally) women, in games and anime etc., depicted almost like any young character, but with bigger "assets" and labelled as milf, aunt or smthg like that.
Its a fantasy world, ppl can be older or whatever author want it to be. If U are fixated on "originals", then maybe u lack of imagination, if it's just age matter, maybe u have issuses with that cp urself? It is not a shame to seek medical help. :)