There are dedicated kids clubs on Galaxy - remember this is a 5* line so there will be fewer kids then on say RCI or P&O. I have heard that the kids clubs are good and they practically get personalised service.
There are children’s clubs for varying ages and yours would be in the Admiral T club, the eldest one. These clubs do not run throughout the year but at the periods when children are most likely to be onboard. It would be politic to enquire if they are running before you book. I am not sure whether these activities are continued whilst the ship is in port. If you are doing, as I assume the Galaxy’s eastern Med cruise this year then there are only two sea days and the other days are spent in port. Make of that what you will, but to get more specific help ring Celebrity on 0800 018 2525 and ask them….. hope this is helpful…..Nei.