Now I'm just a nursing student, so I could be wrong. But isn't charge nurse a position for someone with a lot of experiance. They tell other nurses what to do. At least that's what I thought they did. I figured most people aren't ready for that position until they have a few years of experiance in AT LEAST. Well I'd talk to your supervisor and let them know you don't think you are ready. Good Luck I hope it works out!