I am 70, long standing close friends range from 60 - 85. I have other accquaintances/friends but not in the close friends category who would be younger.
I'm in the middle of my close friends age range.
Most of my close friends have come from my employment days, are of at least 20 - 23 years' standing, and are still great friends even though I've been retired 11 years. We meet up regularly, one friend at least weekly, text/whatsapp often.
At short notice (30 minutes) we can head to the movies, go for a walk, or be a needy shoulder. My dh knows all of my friends, a few better than others.
Two of them I could without doubt ring at 3am if I had a problem, which says a lot.