I am planning my first Disney cruise for my 30th birthday in 2015 and am already planning (and saving) for a royal suite. Neither DH nor I make a ton, nor do we have a ton of extra money just sitting around. What I do have is a streak of miserable birthdays and I really need some extra magic and something to celebrate. Because we are planning to take the extended family (I'm hoping there will be about 12 of us) we like being able to combine some rooms and also have that central location available. I may come back and decide it wasn't worth it, but I'm pretty doubtful that will be the case!
Hopefully your B-day is during the off season to save money. With 12 people if you plan on staying together you will at least 2 cabin on the classic ships and 3 cabins on the new ships.
On the new ships to get 2 cabin to join the Royal the the Cat. T in between the Royals doesn't have an exclusive access. The way the 2 Royals and the Cat. T are setup they have common hallway so they can be connected without going into the main hallway.

