I have done both Adults Only trips and Family trips. The times I've done the Family trips were because either someone I was joining on the trip preferred that date or the trip was not available as an Adults Only (like the Med Cruise add-on and the first year of the Danube River Cruise).
While I had a perfectly fabulous time on those Family trips, I still prefer the Adults Only trips, and that's what the majority of trips I've done have been.
I agree with what
@thanxfornoticin said about the Adults Only trips.
I tend to prefer shoulder season trips, which mostly end up being Adults Only. For a long time they were also generally much smaller groups in the shoulder season.
I also have *nothing* against children. Luckily, most of the children on the trips I've done have been seasoned travelers. But I just find I like the atmosphere of the Adults Only trips better. I find that people allow themselves to be more "child-like" when they don't have to worry about Adulting for the kids. And the Adventure Guides interact a bit differently when they're herding adults vs having to spread themselves out over taking care of the adults *and* herding the kids. Again, there was nothing wrong with any of the Family trips I've done, I just prefer the Adults Only.
I've found that the age ranges for the Adults Only trips really varies a lot. Some of the trips, it's skewed older (50's to 70's), but some have also had several younger people in their 30's to 40's. Plus there's frequently people traveling with their adult children (usually in their 20's). And really just everything in between. The Adventure Guides are really good at making sure everyone is covered, and that people who are slower for whatever reason don't hold back everyone in the group, and that those who are more athletic don't stress out those who aren't. It's one of the reasons I love ABDs. The range of activities and people is part of what keeps it interesting.
I mean, it's always possible you might end up being the youngest people on the trip (although you didn't indicate how old you are). But I don't know that I would consider that to be a problem. My first "big" trip was an Alaskan cruise many (MANY) years ago, and I was by far one of the youngest adults on the trip, and I still had a great time. But that's just me. YMMV.
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