M.J.
I would use a travel agent if you're unsure of where you want to go to or which cruise line. An agent can point you to the right choice and also make sure you don't go during hurricane season.
Most cruise lines have children and teen programs now, so I'm not sure any cruise line is better than the other. They all do have different structures, though. For instance, we like Norwegian Cruise Line because of Freestyle Cruising -- no set meal time, no assigned seating and a casual dress code.