Yeah well if you want to really go Old School just talk to my Mom. She is almost 95 and does not even talk or look it. My Dad (deceased) was 3 years younger than her and they were married for 30 years.
My husband is 7 years younger than me at my age 52 and we are a compatible match. I still get carded when I go to buy Beer. And my daughter is almost 21 and I can't see telling her to marry 41 year old guy. I'm pretty sure she would be grossed out (not my feeling but hers)
I'm not saying that if I had met a much older guy instead of my husband that I would not be with him just because of his age. There are so many variables involved.
My point is is that it matters who the people are that hook up with each other, some people age at different rates mentally and physically. There really is no rule.
You just need to keep in mind that - age is a matter of mind - if you don't mind it doesn't matter LOL