I can't place a number on it. To me it's more a maturity/common interest gap, and that can fluctuate wildly with individuals.
I have a 44-year old female friend who married a 23-year old. It's kind of crazy, given that she's old enough to be his mother, but she's kind of immature. She dresses in a way that makes her look like she's in her early 30s, her body and face look like that of someone in their 20s, and she tends to be pouty and act like a young girl.
Meanwhile the 23-year old is quite mature for his age. Both of them are very close friends of mine, and as crazy as the age numbers are, I'd say they make a lovely couple. By a miracle, they also ended up having a child together recently.
Tbh age ain't nothing but a number. It cannot define how two people feel about eachother. If it is getting weird for either party best to leave it alone. Cause you two are in love doesn't mean the world enjoys it. Something to think about peace.
Age is just a number. It's really about how they connect.
It depends on how old you are. A 10 year gap for an 90 year old is nothing but I'd be geeking out if a 14 year old dated a 24 year old. So I think it's smarter to think about a the age gaps in terms of percentages of thier life. 10 years is 10% of a 100 year olds life. It's not much. 10 years is 50% of a 20 year olds life. So if a 20 year old dates a 30 year old they've literally lived that twenty year old's entire lifetime plus another half of thier lifetime and that's a little creepy. 7 years is 50% a 14 year olds life so it feels creepy for them to date a 21 year old. So in my opinion of the age gap is more than 20% of your life time you shouldn't do it.