How will my baby be affected if my due date is wrong?

Is anyone convinced on the science of that plastic wheel the OB docs spin in order to find out your baby's due date? I have to say that I am not completely convinced that it is accurate. My husband and I are getting ready to have our second child and due to complications the first time around we're having another c-section. For those of you who are not familiar with c-sections, typically if the docs know ahead of time that you're having one they will schedule about a week out from your due date. I went to see the docs to confirm my pregnancy and I was hesitant to tell the doctor the date of my last period because it was two weeks off from when my husband and I actually conceived. (We practice without the use of condoms or birth control and have been together 11 years, so we have always been sure when there is a chance of pregnancy) I told the doctors this and they didn't seem to be concerned, they said it wasn't really a big time difference, but I feel differently. What if my baby needs that extra week or two in my stomach for final developments or whatever else. My daughter had a lot of breathing complications when she was born and she was almost 4 weeks early. According to the scheduled c-section this baby will be 2 weeks early. I guess I just don't like the idea of forcing the baby to be born. I would prefer that I go into labor and then the docs do a c-section then. That's what happened with my first and besides her health issues everything went fine with the surgery. What do you think I should do? Do I press the issue with my OB or place my trust in them?