Hi, I am bringing a 2 year old and a 3 year old on a cruise in the fall to the Bahamas. One of the excursions is swimming with the dolphins. Kids 3 and under are free. Has anyone brought children this young before? Is it difficult? We live at the beach, so they are not afraid of the ocean, but never have been around marine life before. Not sure what to expect or if I should even attempt it.