The opposite of "gotten ready" could be "unprepared." This means that you are not ready for the task or event that is about to take place. Another antonym could be "delayed," as getting ready usually implies being on time or punctual. A third antonym for "gotten ready" is "undressed," as it suggests being in an informal state and not having put on the appropriate attire. Lastly, "neglected" could be another antonym as it means to ignore or not take care of something, which could include not getting ready for a specific occasion or task.