Personally, I battled this with my last pregnancy. Here is the thing, if you are ABSOLUTELY CERTAIN of your CONCEPTION date, then I'd trust your "due date". We are this time, last time not. Even first trimester u/s can be off by 5 days. So, the reason past 42 weeks is scary is because the risk of still birth goes up. Not my much, and not enough for me to induce at 42 weeks, but that's a personal decision. Post dates babies are very rarely post mature babies, even at 42 weeks. I'd recommend reading Medical Myths VS Research Realities, they have a whole section on post date babies, and it's very factual, and most MW have a copy or know another MW who does.
I would worry about NST till 42 weeks, that's just me. I would though keep track of baby movements, and if you find that baby is moving a lot less or a lot more, then I'd go in for NST. Pick a time of day, usually the same time, after the same activities, like, after dinner for ex, and count how long it takes baby to kick, move, wiggle, jult, 10 times (hiccups don't count of course). It's ok if it takes 1 hr, or if it takes 2 minutes, as long as that is what is consistent for your baby. This is something you can do now, to keep track on "normal" for your baby. If for a week it takes 10 minutes to get to 10 movement, and then one day it takes 1 hr, and then the next 1.5 hrs, I'd tell your MW right away.