My son and his friend both 17+ are at the age where they think of themselves as adults and not teens. Somehow, they feel like they will be hanging around a bunch of 13 yr. olds. Can they do some of the adult stuff (other than drink) since they are up there in the teen age? Are there alot of older teens on the ship? I know that they wanted to take avantage of the spa. Would love to hear from ya.