Mission trip to Cambodia?

Hi. I'm going to help out on a mission trip to Cambodia, but I am kind of apprehensive about the trip. I live in the U.S. and have traveled across the U.S. by plane 9 times or so, and I have no difficulty doing so. But I am a little nervous flying overseas for 14 hours with China Airlines (who from what I've heard do not have an excellent reputation when it comes to safety). I also have to fly with Bangkok Airlines, but I do not know anything about them. On top of all of this, I have never been outside the U.S. (except for Canada), and I have no clue what Cambodia is like. I am also a little nervous about the amount of disease in Cambodia. I am really excited, but I am kind of apprehensive about the trip. Any suggestions will be appreciated! Thanks!