I would suggest you to have an demonstration of your dance in front of your parents and near and dear ones. This would help you to have a brief idea and built up some confidence. The other thing that youshoudl keep in mind is that the feat that you have achieved is indeed a very good one to perform classical dance on a stage at the school level is in itself a very big thing. So, be assured that the audience would be just amazed about a kid performing so beautifully, so just give it your best shot and don't be over cautious about the way you look and the way you perform. Just let it go in a normal way and everything would be fine. Good luck for your performance!