When I taught improv to high school kids, I had to tell them they couldn’t use the costumes right away, not because costumes are bad, but because everyone’s first instinct on stage is to hide. Everyone wants to put on a space helmet and googly eyes and glom onto the back wall of the stage shouting “Myyyyyy naaaaaame issssss Cheeeeeeeeto Maaaaan” in a funny voice. So I would say, okay, kids, first thing’s first. Let’s get you comfortable with the concept that you, yourself, belong on a stage. After that, we’ll get out one small wig and we’ll take it from there.