New job fears!

New job fears! I'm starting a new job in a few weeks that involves a basic limited ammount of communication, not much, just knocking on peoples door and explaining what I'm there to check, not more than a sentence really, but the fear is now starting to kick in, I'm already anxious about it.. I rehearse every day what I need to say, but of course we all know where that leads! At my age now, living my life with this I should know better than to stress myself out, i don't know if I should just turn this job down and stick where I am, in my comfort zone, but also in a job I no longer like doing..