Do what your doctor say because what if he's right and something goes wrong with your baby...
Weight predictions are very often incredibly inaccurate guesses. Your doctor DOES NOT know for sure how big your baby is - and even if you do have a big baby, your doctor can't possibly know that your body can't deliver him vaginally. My son was 9lbs and I didn't have even the smallest tear - that was two days after he was "estimated" at 7-7.5lbs.
My suggestion - refuse to schedule a caesarian. You know you can deliver vaginally. Your body knows what to do. Trust yourself. Trust your body. Trust that no midwife in the land would make the suggestion your doctor did and if a midwife can deliver bigger babies then so can doctors. Sometimes you have to stand your ground as the patient. You have the right to refuse. They can't cut you open without your consent. Trust yourself.