OMG a ten pound baby?

They measured my baby and are projecting that he will weigh close to ten pounds! I am SO terrifiyed! My first born, the projected him to be about 6 lbs, but he weighed more then 8, and he fractured my pelvis. if they guess this baby is gonna be10 lbs, are they going to be wrong and have him weigh 12? I'm only 5 feet tall, and not pregnant, weigh less then 110 (I have only gained 24 lbs this pregnancy, and I am 34.5 weeks right now). should I ask for a c-section? will they let me go full-term? I honestly think a ten pound baby might legitimately kill me.