Hi I'm doing Primary but thought I might be able to help you! I have experience but have been for an interview already. I don't think having any experience will go against you as such, but you may get asked questions like, 'Tell us of a time...' and scenario questions where they'll want you to talk about your experiences. When I went for my interview they asked me a lot of these questions. How far away is your interview? Maybe you could get some experience beforehand? Sometimes even just a day in a school will really help, and will make you feel more at ease when attending an interview! Good luck!