S.B.
As long as the baby is growing with the due date you were given it should be fine. Of course the exact due date is more than likely wrong as every woman's body is different and every baby grows at their own speed.
With my first I know for a fact that she was not conceived when they say she was as I was out of town for 2 weeks and it happened to be in the middle of those two weeks would have been conception. But she was born 2 days before her due date.
The same is true for my second. They say the baby was conceived at new years but my daughter was sick for a whole week with a high fever so there was no loving then!! We will see when this one is born.
Just go with what they say more like a guide than an actual day. Don't stress, Drs like to think they are right.