Singing blissed?

i have a problem i can sing my lola told me i have a nice voice though and the other day my teacher asked me to sing in the school spelling bee as an intermission then my teacher said okey then i changed my mind but this time we are going to sing s trio but still iam quiet nervous because the one iam singing with the other one is like a popstar in our school her popularity is almost outrageous though if i turned down the offer i will just still stay the same unknown me .. what do you think i should do ??