When you're pregnant....?

and you're getting close to your due date, do you go to the doctor and they tell you if you can have the baby as you planned? Or is it usually a last minute thing if your birth plan has to change? Why I'm asking, is because I'm planning on having a natural vaginal childbirth with no epidural. I'm hoping that won't change, but I was wondering that if it does, and I have to get a c-section do they normally know ahead of time by the way the baby is positioned?