One thing you all have in common is you all sound so very enthusiastic, and that, at the end of the day is what they want! Be genuine, warm, and whenever a difficult or unexpected question gets thrown at you which could make you feel inhibited or whatever....... just tell them, "gosh, I hadnt prepared for that, please give me a moment or two to think about this one in more detail" and remain polite, and you will do fine!
