We will be in Nuevo Vallarta 12/31 - 1/7 (can't wait!) We have a 15 yr old who doesn't really want to do the dolphin encounter (or anything else involving family)and a 13yr old who really wants to try it. Is it worth the money? Do we need to book it before we leave? Also, is water park admission included in the price? I will be extremely grateful for any advice.