Yes, they will be old enough to be in the disco and they should be allowed in the Casino... But I don't think they will have any activities directly aimed at their age group other than a singles party. But, I also have not had the need to pay that much attention to that age group's activities, so I could be wrong. I'm sure they will find plenty of entertainment to keep them happy.
Carnival Cruise Lines:
Fantasy 90, Celebration 95, Victory 05, Conquest 05, Spirit 6/06, Freedom 6/08, Holiday 7/08, Victory 6/09, Valor 9/09, Dream 6/10, Splendor 8/10,Conquest 8/11,Magic 11/11,Triumph 4/12,Spirit 7/12,Freedom 11/12, Triumph 2/13 - The fire cruise
NCL Dream October 2006, RCCL Mariner OTS June 2007