Sunny, I don't know which singles cruises your friend is referring to, but I have done many and find that most in the groups range in age from late 20s to late 40s, especially on the shorter cruises such as 3-4-5 days.
Go to the Singles Section of Cruisemates and check out the Singles Cruise Calendar, then e-mail me to ask about specific cruises, and I will do my best to help you.
I am noticing that more and more agencies are organizing cruises for older singles, which I think is great as the different interests of age groups vary.
Pat Hagan, Singles Editor, Cruisemates