Younger generation these days certainly don't care. I've gone to parties that were borderline high school parties - mostly recently graduated 19-20 year olds, and not even a blink seeing my near 40 year old ass there.
Then again... I don't remember taking much notice of such things when I was that age. I had other things to think about at the time, and the age of some old dude hanging out certainly was pretty low on my priority list. It may just be that many people are conditioned to think poorly of such a thing between 20 and 40.