How can I get over my fear of opening up in class?

Hi everyone. I have a little problem opening up I guess. Well today in Theatre I did good. Our excercise was to pick any emotion and introduce ourselves. She showed us an examlpe by saying; Hi my name is Mrs. Maenner, and I had a great summer. But the thing was she was crying! Yes my drama teacher is so good at her job that she can make you believe her in anything. Her emotion was sad. But anyways I picked excitment. I did good! I said Hi! My name is Chelsea And Im a junior! And I acted loud and excited. She clapped and started laughing, and it doesn’t sound so funny on here but it was actually. And I got one of the loudest claps so I was happy. =)

But anyways after everyone was done she announced, “Tomorrow will be tryouts (for our play) (it’s a drama this year I think) and I want you to impress me!” She said this to everyone. I need help! How can I impress her? It was hard enough for me to say that today but I survived but “HOW CAN I GET OVER MY FEAR OF OPENING UP TO MY CLASSMATES?” Because I am actually a really funny, nice, friendly person but only my friends see this and know this. But yes can you answer my question? Thank you for the help everyone! <3