They have packages you can purchase to help celebrate a birthday or special event. For 74.95 you get a souvenir buoy with your special message delivered by your dolphin, cake and photo. Or they off a deluxe package for 174.95 which includes the same as above plus a disposable underwater camera, t-shirt, and video of the event. Obviously, these charges are in addition to the normal admission fee.
They also offer packages for marriage proposals.
We have never purchased one of these packages, but they sure sound like a great way to celebrate a birthday! Since you are paying for it, I don't think it matters if it is not on your actual birth date.