I would call a travel agent and talk to them. Tell them your situation and how much you can afford to spend. The T/A will advise you better then anyone else can.
Personally, I wouldn't want my 14 yo son and 18 yo daughter bunking together as they would probably kill each other, plus no one under 21 can be in a room without someone older also occupying the room.
I have heard before that a suite might just be the ticket as it can accommodate the 4 of you more comfortably.
Women were made to love, money was made to spend. Life is something buddy, you'll never live again.
from the song..."Joe sure knows how to live" by Eddie Raven.
Carribean Princess 07
Carnival Valor 08
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Island Princess 09
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Norwegian Pearl 11
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Independence of the Seas Feb 14