In both of of my bands I'm considered a mere slip of a boy at 48. All members of both bands are roughly ten years older than me.
One band plays Mod, Northern Soul & Ska and play to audiences from that scene, so generally around the age that the late 70s/early 80s revival scene was relevant to them, some older from the original 60s era but plenty that are younger.
The other band is amped up acoustic covers of pop songs done our own way. We happily play Dua Lipa, Girls Aloud, Britney Spears, Katy Perry, etc to a 20s to 70s age range. We also play an assortment from any era but the above shows if 60 year olds can play 'girl group pop' to young audience members then anything goes.