I should probably change that as some will likely take it as some sort of strict criteria.
I'm not thinking of any particular age group. Just looking for folks who are easy-going and like to work as a team, help slower/newer players out in the group, etc. .....the opposite of rude, annoying people with self important attitudes trying to impress everyone else in the group that take themselves or the game too seriously. Perhaps more mature in that sense although even the use of the word "mature" tends to rub some people the wrong way.
I'm at the half century mark myself although I've had PSN friends from their 20s on up to my age.