If you had said should I get the 16' Mistral or the 27' Ericson, then I might've leaned towards the smaller of the two in order to gain experience. However, at a 5' difference, you might as well move into the larger of the two that allows for more comfort for the family. Like someone posted above me, there's not a "ton" of difference between sailing the two. Having said that, are there any clubs nearby that you can join? And yes, you can join without owning a boat yet; a lot of people do. I ask, because if so, you could always let your club-mates know what your intentions are and could more than likely be able to crew on boats of both sizes so you can get a feel for the difference, if any.