I told them that I had another KFC interview very soon, which was true, I think this also made them want to get back to me faster because they knew that I could be taking the other job instead of theirs if they offered it to me. This also showed that I was eager to work. Maybe don't mention previous interviews that you haven't been successful in, but if you want you could probably just say that you have another interview the next day for eg. Maccas or something, so they know if they want to hire you, then they should do it quickly, because I know that that's a little interview trick... but if you don't want to lie (which is probably more morally comforting haha), then just tell the truth, if it's your first, say it's you first. They might not ask you this one though anyway. If they ask if this would be your first job, that's another thing. I said it would be my first job, which is true.