For my Harvard interview, my interviewer was super friendly. We had a very nice conversation about my EC and personal history. I moved around a lot growing up (from a small rural Asian village to NYC and around the states) however, I didn’t mention it right away. I let the conversation flow and only answered when he asked if I lived in NYC all my life. He was surprised and told me he was glad he asked the question or else he wouldn’t know things like that about me. My suggestion for your circumstances would also be to wait until he or she asks about your “high school”. If you didn’t have a chance to talk about your unusual circumstances, don’t worry about it. I’m assuming it’s included on the common app additional info so your AO will know. I wish you the best of luck!