Im scared to sing in front of people?

Hi...Im 11 years old and i really want to be a singer and a actress when i grow up. I am kinda good at singing but i cant do it in front of a crowed. Is it because i am picked on, or is it just being nervous? i am scared...i failed chorus...dont say "how do u fail chorus?" i failed because I AM SCARED TO SING! HELP!