I'm in the same age-range as you and we were faced with the same delima for our first cruise. My boyfriend and I have very particular tastes so we wanted to find the right thing for us. When you consider your cruise my travel agent said you want to consider lots of things including your age. It took me FOREVER to decide which one to go with because of this. The first thing I looked at was destination. Once I found where I wanted to go that I could afford, that narrowed it down to Royal Caribbean and Carnival, which happen to be the two suggested cruiselines from my travel agent, for our age group. Carnival is known as a "Family" cruise line and tends to have lots of children and familys as well as teenagers and young adults. But we chose Royal Caribbean because we liked what the boat had to offer for one, and we tend to have extravigant tastes for our age. (Like fine food, champagne, cigars, gambling etc. --our boat has a cigar lounge and champagne bar) So I don't know if any of that helps at all but I would suggest you pick your destination and price range and that will narrow your search. Then check some of the boards about the different lines to decide which one will suit your interest best. They might help too. And as for the jeans... honey it's his vacation...he's paying for it. He can wear whatever he wants! And you don't even have to go to the formal night...there are other places to eat on the boat. I'm so excited for our first cruise. I hope you guys have a great time on yours!