Today's cruiseships all handle rough seas quite well. On one of our cruises we encountered seventy mile winds and all the ship did was rock a bit.
Not to worry you will be fine.
Carnival Liberty New Year's Eve 2007
Liberty of the Seas 5/2008+11/2009
Allure 1/16/ 2011
Booked Vision of the Seas . 2/14/2015
Booked Allure of the Seas... 2/21/16 *Last Gang Cruise*