You have gotten a lot of great suggestions. My husband and I had gone on 9 cruises before I lost him, mostly on Royal Carribbean and Holland America. The only thing I can add to the great replies already made is my memory of our very first dinner in the dining room on our first cruise.
My husband and I were feeling intimidated, as we'd never been on a cruise before and assumed that the other 6 couples sharing our dining table were rich and did this kind of thing all the time. When we were seated at the table we saw so many knives, forks and spoons that we were worried we would do something wrong. As we were getting to know the other couples at the table, one of the other husbands said 'I have no idea what to do with all this silverware'. Well, that comment broke the ice, and we discovered that all of us were on our first cruise; two couples had won their cruises in a contest, another couple was gifted the cruise by their children, and the rest of us had saved for a very long time to go on a cruise. Everyone relaxed after that, and we had a great time talking about our day's experiences every night at dinner with this group.
Thankfully, the service staff would remove unneeded silver when you made your selections from the menu, and if you were still confused you just had to give them a look and they would discreetly point at the correct silverware to use for a particular dish when they placed it in front of you.
I guess the moral of the story is that most people worry more about how they appear to others than they worry about how others appear to them. So please don't avoid the elegant dining experiences - you'll have great company and a lovely experience.
PS: On another cruise, the two couples sharing our table weren't as open or easy going, but it became a lot of fun for my husband and I to take bets before we went to dinner on who would complain about what first, etc.