she wants me to sing with her

We are 17 and she sings all the time. I have been told a lot that I can sing.  We sing as mucking around but she asked me to sing with her ( harmonzing) for her school major in front of the whole school. I'm out of school now but I have severe anxiety. She knows but wanted to give me the opportunity. I kinda want to do it but my anxiety is so strong right now along with my depression. I don't know if I'm strong enough to sing infront of the school and my year group in particular. I left in year 10 and "we" are in year 12 now. I'm so bloody scared I don't know what I should do 😭😭😭