I was two weeks late with my first! I'm now 38+3 with my second and no labor yet.
Yes it possible I was due April 10, 2008 and had my son April 11, 2008 but I was induce
My first was 6 days late before I was induced and my second was 11 days late before they induced me. My SIL was late and induced with her first and third but her second came early. I've heard of a LOT of people delivering early though. I really think it has a lot to do with you, your body, and possibly genetics so there isn't any way to know ahead of time, and sometimes there isn't anything you can do to help change it. I tried all of the tips to get labor to come early and nothing helped, so it really changes from person to person.
I was 3days before my due date!! Everyone's different tho :)