I was recently made a supervisor at my job (officially), but tonight was awful because I was working with high schoolers and none of them were taking me seriously. They never did before I was promoted, but even now they still don't. It was one of the most stressful nights I've ever worked because they didn't listen whenever I told them to do anything, or they'd do it ridiculously slowly and we'd fall behind on our tasks.
Do you have any authority as they supervisor? I'm assuming they're part-time, so could you reduce hours or fire any of them?