The clubs exist only because of the trojan work of the older and former members, I doubt there’ll be one with a majority membership of 20 year olds. You’re looking for a running group if there is such a one. Normally runners train with people of similar abilities regardless of age.
It would also depend on what event you plan on doing? Might help. I recently just left my 20s and was in a club with only approx 5 runners in that bracket however there are plenty older to link in with.As said above the general demographic of most distance/marathon runners would be a bit older however there are exceptions. The big clubs such as Clonliffe, Raheny, DSD tend to have the larger base of Junior runners (u20) who progress through.
