Open Question: First Day on the Job tomorrow at Sesame Place?

I start my first job ever tomorrow at Sesame Place as a cashier at one of their stores. I am pretty nervous, although I am only working for three hours. I figure it won't be that crowded since it's a Friday and I am working from 3:30pm to 6:30pm. I hope that it is more of a training session since my orientation didn't go so well. One person stood in front of one cash register in front of 30 people (including me) on a very hot day and showed us how to use it in an area no bigger than your room. That was like a month ago, so I kind of forgot everything. Is that bad or will they probably give me a refresher tomorrow? I understand that with my first job, I am pretty much guaranteed to make mistakes and that is a good way to become better at my job, by making mistakes. But I just wanted to hear from some one else that I will make mistakes but that's a good thing, and that everything will be alright. Thank you all!