We came real close back in January with piece of luggage similar to the one you described. It was barely under the weight limit and we we warned not to pack anymore into it for the return trip. The ticket agent slapped big red & white tags labeled "HEAVY" all over the piece.
Next time we're taking my brother's advice. Lay out all the clothes you plan on taking and put half of them back in the closet. We found it a good rule of thumb. Half the clothes we took along came back unused. Our next cruise is also 11 days so we really need to watch what we pack.