Hi mistermikeydee, and welcome to cruise-chat.com. I've done this cruise twice, once on Carnival Destiny and once on Carnival Victory. (If only I could do Carnival Triumph this year to make it complete.) In any case, it's a nice cruise and you should find a variety of ages onboard during the summer. We also found much to do in the evenings...good entertainment, clubs, bars, etc.
Dave is right in that it is not a cruise for sunning, although it can be warm in Canada, yet there is still plenty to do. If you stop in St. John, you may have the opportunity to ride the Reversing Falls Rapids as one of your excursions.