First, welcome to the boards!
Second, as for an appropriate age? I don't have any children, but from observation, I've learned some things. There are differing views on kids and cruising...
Ask some, and they will say that they will cruise with a 6 month old, as long as they get to cruise with the Mouse!!
Others say that they would rather wait until the children are old enough for the clubs. That way you can get alone/quiet time while the kiddos are in the clubs.
As for the clubs, the rule is anyone 3yrs and older (and completely potty trained) can go to the kids clubs, which are included in the cost of the cruise. Anyone under 3 (or not potty trained) must use Flounders Reef, which is the nursery, and this costs extra.
Another issue with age is the pool. The Mickey Pool is open to potty trained children only-No swim diapers. There is one tiny wading pool for tots (one of Mickey's ears) and that is the only place swim diapers are allowed.
Those are some of the concerns I've seen expressed here. But that is CERTAINLY not to say that you shouldn't go!!!
It's completely up to you. I've read trip reports from folks who have gone and taken young children, and still had a blast!
I think the best way I've ssen it put here is this: Your cruise experience with a baby may be a little more hectic than that of someone else who has an older child or no children at all. BUT...I'll take a "hectic" day on a
Disney Cruise any day over a good day at home or at the office. At least on the cruise you don't have to cook or clean, and you can spend all of your time enjoying your wonderful son!!!
Oh! And another tip I've seen here-When cruising with small children, a lot of folks try to go for staterooms with verandas. That way when your little one is napping, you have a sunny place to relax/hang out/read a book.
Like I said, I don't have any experience cruising with children ,but these are things I've seen posted here before.
Hope that helps!
-Christal