We are going on a 3 day cruise in April. We would love to take our two boys, (5 and 4) snorkeling. They love to swim, but I would make them wear a life jacket during snorkeling. I bought them some gear and they have been practicing in the tub. Has anyone had kids this young be successful at snorkeling? I am curious because all the excursions for snorkeling are for older kids, 7 or 8. I was hoping to do it on our own at Castaway Cay.