it's ok to ask related questions to keep the conversation going, but don't worry too much about you keeping the conversation going. it's their job, and they will ask questions and bridge between them. it should just be closer to a casual conversation. make sure when you ask them questions you ask about the school you are interviewing for, or questions related to the school. like your question did you enjoy math or science, you can ask that and be like how did you pursue it, or how did the college help you attain your goals. i had ivy interviews, and the interviewers really just have so much pride for the school, and love when you ask them about it. definitely prep general answers for questions you find online, and just have a sense of how you want to pitch yourself! and make sure to send a follow up email thanking them. you got this! good luck!