They will bring a cake to the table and the waiters will gather around and sing Happy Birthday. You will find out your dining rotation when you check-in for the cruise. It will be on your boarding pass. The rotation will be designated by the first initial of the dining room. It looks like your going on the Disney Magic. The dining rooms are Lumiere's, Animators Palate, and Parrot Cay. So it may look like this on your boarding pass LAPLAPL. That would mean first night in Lumiere's, second in Animator's, third night in Parrot Cay, etc. Palo's is reservation only and made once you are onboard. It is $15 per person to cover the gratuity. Formal nights on a seven day cruise most likely will be 2nd night and 6th night.