This is a copy and paste of old post I have done before, keep that in mind when you read them. We have since then done two more cruises, in May we will board our daughter's fifth cruise. She will be 16 months by then.
This is my experience, your baby will be in the center of attention. You might not want to let a lot of people thouching your babys hands since they put them in the mouth all the time. Before you go on the cruise, get your baby used to noisy environments like resturants and shopping malls. This will help the baby to get used to a lot of people. Breastfeed your baby, then you always have the food ready and your baby have a protection from the milk and aren't affected by germs from food. Bring a lot of nappies, we had 330 with us for our cruise. We keept score of how many nappies we used the weeks before the cruise, 15 - 21 each day... We did have 100 + nappies when the cruise was over, but better safe then sorry. Meraviglia have very nice public restrooms with changing tables for babies but when you are in your cabin you will need something to put your baby on when it's time to change the nappy. We bought a blow up thing from IKEA and it worked very vell. Ikea Skötsam. And for public places we used Libero Mats to put on the changing tables. MSC did a wonderful job making it easier for us. Priority boarding, opened up a office for my wife to breast feed our baby on embarktion day when our cabin wasn't ready. Helped us with the stroller when we got on the ship or when we got off. Bring a smaller stroller that can have the seat folded down completly. We used a Baby Throne / Yo-yo stroller. Don't have a lot of plans for the ports of call, traveling with a baby is VERY time consuming. Bring a pair of Peltor Kid hearing protection with you and keep it in the stroller, now and then your baby will need it.
After the first cruise we bought a Graco stroller that can fit a baby seat and a Stokke PramPack, both are great! We have a very similar stroller as this one, but not exactly the same:
Stokke PramPack https://www.youtube.com/watch?v=VB6QACpqU9w