Jewels, depending on the sailing, NCL offers upgrades only from certain categories to other categories. It could be that you're booked into a category where no upgrade is being offered. NCL won't upgrade you "just" because there are 14 of you traveling together. In fact, on most 7-night sailings, you're not considered a "group" unless you are filling a minimum of 8 cabins. If someone offers you something, it could be your travel agent, perhaps in the form of a gift of wine or something else.