We will be traveling with a 17-year-old senior in high school (our daughter), as well as her 18-year-old best friend (also a senior but about four months older than our daughter). According to Carnival's website, Club O2 is for 15- to 17-year-olds. How strict is this policy? Is it solely dependent on age or will they take into consideration that our daughter's friend is still in high school? Thanks in advance.