Oh you MUST go places today and when people ask when you're due, say 'Today'. Or even better, say 'a few days ago'.
People's reactions will make up for all the stupid crap people say to you when you're pg. It's priceless.
In my vast, vast experience, post-term babies have a much easier temperament. My DD2 is also a complete overachiever (crawled at 4.5month, walked 5 days past her 9mo birthday, etc). We call her superbaby.