IF they waves are hitting your window on deck two, you are in some rough seas. There are crew and utility decks below you so there is at at least one more deck before you get to the water line.
I guess the real question is "to low for what?" Your cabin will be the saem as any others of the same category. Its not like you would be in steerage or something. And if the water was truly an issue, then the ship would have sunk a long time ago.
Carnival Cruise Lines:
Fantasy 90, Celebration 95, Victory 05, Conquest 05, Spirit 6/06, Freedom 6/08, Holiday 7/08, Victory 6/09, Valor 9/09, Dream 6/10, Splendor 8/10,Conquest 8/11,Magic 11/11,Triumph 4/12,Spirit 7/12,Freedom 11/12, Triumph 2/13 - The fire cruise
NCL Dream October 2006, RCCL Mariner OTS June 2007, Celebrity Silhouette 2013