It's a tricky one. I'm in my 40's, and I sometimes fancy a ride out with a group/club, but there are a few issues.
Due to work patterns (varying shifts and inconsistent) it's hard to plan anything with any regularity. I mean I may be free for a couple of Sundays on the trot, but then struggle to attend a ride for months. Which makes it hard to be a part of anything which requires reasonably consistent attendance.
In terms of speed, I've done a gently undulating route of 60 miles at an average of just over 16 mph with no stops. (I don't know how good, bad or indifferent this is.)
But I live on the edge of the Peaks, and the cycle clubs seem to head out that way. That's fine, but would I keep up without throwing up!
There certainly seems to be a bit of a gap in the middle, for those who ride at a speed which is a bit slower than racing whippet, but faster than, say the CTC rides.