Beverly,
Does your state not have a law that prevents new drivers from carrying passengers for the first 6 months of having their license? We live in Georgia, and until a teenager has had his/her license for 6 months, they cannot drive with another teenager in the car! Best law ever made in my opinion!
Another law is that they have a midnight curfew until they turn 18. My DS is almost 18 (July), and he's had his license for a year now. He waited almost a year after turning 16 before he got his license. I was glad. I think 16 is truly too young to realize the responsiblities of being behind the wheel.
I am fortunate though. My DS is a good, safe driver. I have to admit though, when he first started driving, I made him call me every time he got TO his destination, and everytime he LEFT to come back home. I've relaxed over the last year though.
Charlotte, it seems so scary at first, but the best thing you can do is relax and let them gain the confidence they need. They can sense your distress, so the best thing to do is RELAX!! (Easier said than done, I know!)