I agree with Mike. Also, on my last cruise, my brother was 18 and I was 17.. We both hungout together the whole time, even in the Teen Club. It's not really a problem, especially because we spent less than 1% of the time in there anyway...
Royal Caribbean- Vision of the Seas- Dec. 31, 2006 - January 7, 2007
Carnival Pride- Dec. 18-25, 2005
Celebrity Summit- Summer 2004
And Many more that can't remember off the top of my head!
Cruise Lines I Have Been On
Carnival (many times)
Royal Caribbean (many times)
University of Arizona '12!