She has not been Kate Middleton for two years, she is the Duchess of Cambridge.....and how on earth does the OP know what the woman's actual due date is !! No one knows. The fount of all knowledge The Daily Mail decided among themselves it was about two days ago....and therefore she is now late !!!
Would William be miles away playing polo if she was bang on due date never mind late. Would Pippa be abroad as she was a few days ago. No....... I think its safe to say when all relevant parties start gathering and no one is moving a muscle.... we are far closer to what is due date.
Apart from Kate, presumably?