Terrified

I was sitting at dinner with my wife the other night and came to a major realization: I am going to be responsible for the education of at least 60 students; specifically in the area of physics. Even Advanced placement. For some reason, that thought is a bit scary right now. I am trying to write a syllabus for the AP course. I actually have to write and submit one so that my students can have the letters AP on their transcript. I'm not sure why that even matters since it is the score on their test that makes a difference. If they make a good score, who cares what their transcript says, right?
So here I am trying to figure out what to do. I feel as if I have no idea where to start. I mean, I know the subject, but where do I start? It's much harder than I thought.