I won't even consider dating a much younger girl as a dude, I really doubt i'd do it as a chick.
What is an older dude who dates young chicks called anyway, or are there only negative terms for that?

Anyway, if I was gonna be a chick, I would wanna be a young/pretty (also cute) chick for sure. I'd also wanna be a fem girl (not like a tomboy etc), and totally wouldn't wanna be like a manly girl. If I was gonna be manly, I'd just stay as a man.

Actually I have always liked being appreciated, I like doing things for my partner etc, and I want to be wanted etc. That wouldn't really change if my gender changed. In many ways my personality would have fit with a more feminine body tbh, but well, I'm an ogre, i'm not feminine at all, and I find cute women attractive (not into huge boobs, or overly sexual looks etc).

Given the option to change my body though, I don't know what gender I would actually choose to say as. I did love playing sports when younger, and my size/strength was sure useful at times in the past, but I could have had far more freedom to interact with my students if I was female, and I think what I look for in a relationship would have been much easier to find as a woman as well.

But none of it matters anyway because A: we can't actually change gender at will and B: I'm to old for it to matter at this point even if they suddenly came up with the technology that let you walk thorugh a door and be the opposite gender as often as you wanted.