Hello we have seventeen year old six foot one son bunk no problem,built for adults same mattress /bedding as the other beds. have a great time am sure children will love it as much as the adults .
My daughter stayed in the bunk on oceana she is only 5ft2 and 17 but it was a bit of a sqaush.
We are on the same cruise! Our daughter is 12yrs and as a mentioned before the bunks can take adults so kids will be fine.