The main thing is not to fear. If you come the first time and you are afraid of a huge number of high school students and teachers who are watching over what is happening, then just ignore it. Almost all were once in the same situation. And though teachers usually look for all students, but separately for one you will not observe unless you are going to attract attention. And in order not to attract attention, you just need to behave culturally.
If you think that all who go to the disco, know how to dance and do it well, you are wrong. The majority of students had never engaged in any form of dance, and many do not even like to dance. Then why go to a school disco? To have fun and release all the accumulated negative energy. And they produce it, dancing what I want, repeating light movement, and also sing (or even scream). Of course, those who are professionally engaged in dancing, doing complex movements that are hard to repeat. But many just stomp their feet, waving their hands and moving my body, in a word, perform the most simple movements, which lifted the mood. And if they are repeating a large number of people, it not only brings joy but also brings.
Sometimes girls and boys are afraid to dance a slow dance, which is often on the disco. Those who dared, rarely think about this, so also you should not be afraid. In a slow dance no complicated movements, the main thing is not to hurry. On it and slow.
And never stand on the sidelines or corner. If you came to have fun, then have fun. More attention will be paid to people who are sad and watching everything happening. You'd better enter a bunch of good friends and light all together. And don't think about how you dance. Throw all the unnecessary energy and bad thoughts. Just enjoy the disco.