A childhood belief about church

When I was in elementary school, I went to a Catholic school where we took "going to church" very seriously. Our church was right down the road so it made it easy for us to walk there as a class almost every week. Our teachers always told us the basics on how to conduct ourselves during a mass. I was always afraid on doing something wrong so I'd do everything that the priest would do. If he'd raise his arms, I'd raise mine. It wasnt until the end of the second grade that one of my friends standing next to me poked my arm to ask what i was doing. She explained to me that i didnt have to copy everything he does, and I remember feeling really horrible after, b/c I was worried that if the priest saw me doing that, that he might've thought i was making fun of him. In reality for as long as i had been going, I didnt know.