the thing about online ads is they often attract people who can't find a band for good reason. they're assholes. they're just trying to take the fact that they aren't rock stars out on you.

that being said, it's not weird to want people in your age group but it's also not weird to play with people older/younger. it just depends on what you're going for as a musician. A lot of good bands don't necessarily hang out with each other in their downtime. plus a lot of competent/realistic musicians tend to skew older.

from an image standpoint, it really depends on the individuals. i don't think i've ever seen a band where i've noticed or cared about an age range. Someone who's 30 who didn't party super hard in their 20s or took care of themselves might not look that much older. On the other hand, if you're playing shows that a lot of young people are gonna be at, you gotta worry about the potential of them being creepy and predatory.

ya'll being comfortable is the most important thing though. if you want that smaller age range, go for it. you're gonna write better music if you don't feel like you're forcing it and being awkward about having members older than you could definitely make you feel forced.