You made the right choice to get two rooms. If this is your first cruise you WILL be disappointed with the size of the rooms. Cruise rooms are MUCH smaller than even the cheapest hotel rooms. That said, you don't spend too much time in your room so its not a big deal. You will want your kids to have real beds though.
If you can, see if you can get CONNECTING rooms. This is a pair of rooms with an interior door between them. Then, its like having a 2 bedroom suite. My kids are both under 8 so we need to be able to check on them, but you may like this for teenagers as well. Even if you don't check on them at night, its nice being able to open the connecting doors during the day rather than walking out into the hallway.
Have a great time on your cruise!