Welcome to Cruise-Chat. If you're with a group of girls it really won't matter what the average age range is, because you will be with your group most of the time. You can request that you all sit together at the main dinning room for the early or late seating. I've been on a lot of cruises and never noticed any one not having a blast, what ever their age. All the ships have a disco and great entertainment. Plenty of activity for all ages.