We had a Cat. 2A assigned cabin with a balcony, that was in a perfect location on the Penthouse deck just around the corner from the forward elevator bank. We were before the Tenders and had no obstructions. It was only a few decks above those used for disembarkation and one or two decks above the main dining room. Very convenient.
The 2A will be tight for 3 people; however, a Sky Suite would be perfect. Check out the concierge desk when you get onboard to see about an upgrade (about $300) though at Christmas, it may not be possible.
Tight is a matter of what you are used to. I have seen many families of 4 enjoy cabins that some of us would go crazy in. The biggest concern to me would be 3 or 4 getting ready for dinner or whatever in such close quarters. My 2 daughters and I did 3 in a cabin on Carnival a few years ago; did fine, just had to plan very carefully when it was time to shower, put on makeup or whatever.