Hi, and welcome to CM. I'm glad that you've booked your cruise. I know that you are excited and a bit anxious. You really don't have much to worry about. Things can happen anywhere, at home or on vacation. I think everything will be fine.
As for the excursions, they will make sure that you go where you are supposed to go. Everything is set up that you know where to go. Please don't worry about it.
Try to relax if you can. Things will be fine. Enjoy your cruise.