Myself and my girlfriend are in our mid 20's & just got back from our first cruise and really enjoyed the experience. As lots of people have pointed out, Majesty isn't the newest ship on the seas but it's very well maintained and the staff are, for the most part, very nice & professional. We did the 4 night cruise from Miami and it was the perfect amount of time for us as first timers. We had a standard ocean view room and although basic & small (which we expected) it was perfect insofar as it was very clean (twice a day they serviced it) and there was plenty of storage space (we had luggage for a 2 week trip with us).
The only downsides we found on the trip were:
a) the food in the main dining room was average/poor (and we're not fussy eaters!) but there is a very good alternative in the WindJammer which is surprisingly good quality, so we weren't too bothered.
b) the service in the bars (mainly the Schooner & Casino) can be anything from slow and lazy to actually rude and incompetent. I've no idea why these bars in particular - the pool bars actually dealt with the vast majority of customers (especially as we had hundreds of Spring Breakers on our trip) and they were fairly good and friendly - but for some reason, the guys working in those interior bars seem pretty unhappy and it spoiled things a little bit for us as we had paid for a premium drinks package and found it could take 20mins to get served a drink while standing at the bar when it wasn't even that busy....
Bar service aside (and perhaps they were just having an off week!) we had a great time and would recommend to anyone looking for a casual, relaxing & not too fussy short break from Miami.