I'm 33 and have a Catalina 27 in the Northern Chesapeake. I am definitely the youngest at my marina. My dad crews with me frequently, and people usually assume it is his boat. I also race around the cans on Wed. nights. There are two other guys in the race fleet that are my age (they crew on other boats), but all the other guys who are probably twice my age are great to sail and hang with.
It's true that very few of my friends have boats, but some do, although they are powerboats. The funny thing is, every friend my age I take out loves the experience, even those who expect not to like it.