There are good reasons why shell collectors should be relatively mature.
 
Among fossil-shell collectors, young men and women commonly take up the
hobby and then lose interest when they discover the opposite sex. Suddenly
they have no time for field trips on weekends anymore, unless they are
lucky enough to find someone else who shares the collecting bug. When they
marry and have children, often in that order, free time and cash vanish
altogether unless one partner sustains the other, which isn't as
practicable these days as it used to be. A few couples do take their
children on field trips, and of course many more find the time to encourage
their children's interest in shells. When the kids grow up and can take
care of themselves, time becomes available again and the parents once more
have time for shelling. Free-time pleasures become even more important in
retirement. So we should expect shell clubs to have an excess of the
retired, the unemployed, the currently unmarried, the childless, and the
prepubescent, plus the occasional professional. The resulting club members
may make an odd collection, but the mix of ages can be charming.
 
It is also true that children are not as interested in collecting shells,
caving, hiking, building go-carts, or other physical activities as they
used to be. No contest there.
 
Andrew K. Rindsberg
Geological Survey of Alabama