When is an age-gap considered creepy?

EDIT: sorry for the title's wording, my question is about age-gaps between musicians in a band/group/project setting.

I'm 42. Practically an empty-nester, getting back out there after spending my 30's raising kids and building a career.

I understand people specifying an age range when looking for players; generational differences can be hard to navigate and, for a lot of popular music, youth is part of the aesthetic.

I've seen or experienced a couple of things related to age in my area (Minneapolis-Saint Paul, MN) and I'm wondering if other people have seen this too:

• I saw an ad that gave an age range of like 25-35. Then it said "no kids, no creepers". People over 35 are creepy?
• Some ads don't include an age at all. I message, send a sample of my playing, there seems to be mutual interest... but as soon as my age comes up, I get ghosted.

I've been able to get into a couple of projects in the last couple of years, so it's not like there isn't anything out there. But I'm looking for a second project now and it seems like whenever I find something interesting, age has been an issue.

In my experience, older musicians usually welcome younger players, but I haven't found older groups that play stuff that I'm interested in.

How much do you care about age differences? Do you have a rule-of-thumb? For example, plus/minus 5 years? 10 years? 20 years? What's the rationale?

When does an age-gap become "creepy"? I could see it being weird if I was playing with high-schoolers at 42, but what about people in their 20's or 30's?