The point of the interview is to get a better idea of who you are as a person. What are your passions? Why do you want to attend USCGA? What makes you unique? Why would you be a good cadet? Would you be a good shipmate? Does it seem like USCGA would be a good fit for you? The interviewers have not seen any part of your application. They know nothing about you other than what you tell them in the interview. There are required questions that all interviewers must ask all applicants, but interviewers can ask other questions as well. Feel free to go off on tangents, so that the interviewer learns more about you. You obviously want to give the best impression of you possible. They will be providing their evaluation based solely on the interview, so if you want them to know something, you need to tell them.