Due date?

Victoria
Is anyone else getting different due dates? My first appointment they said the baby's due date was Oct. 20, 2016. Now they're saying it's Oct. 14, 2016. When I asked them which due date they're going to go by they said it really doesn't matter since its only a week's difference. I just want a healthy baby but I keep hearing that it's best to have a set date to track the baby.