I asked my OB about this a while ago and he said that our little one would be born at about 38w. I believe it is so that you don't go into labour and wind up having an emergency one, but I'm not 100% on that. But it makes sense that would be the reason.

I'd say when the time comes, to talk to your OB or care provider about your wishes to have the c/s closer to your EDD and get his/her opinion and then work from there. You should be able to have a say in it.

As for the baby being prem, I guess it's possible, but I'd say unlikely as most people have scans etc to determine an EDD and even though u/s can be notoriously inaccurate, they are still somewhat of a guide I suppose??