Agree with the PP's - when you kids will drive depends on your personal situation. My oldest has a car that we bought. It's new, but a small, no frills VW. However, its got an automatic transmission and I really wish we had taught her to drive manual. I learned how to drive on a manual and drove one for years. Automatic is easier, but knowing how to drive manual is just a reasonable skill to have - you never know when you'll need it. I also like the PP's comment about the cell phone! Never thought off that…My DD wants to learn how drive stick and we will probably try to make it happen this summer. Once you get a hang of it, it's easy and like driving a bicycle.
I would keep the 16-year old car, especially if it's not too big. Our original plan was to give my DD my old car that can seat 8 people and then I would get a new car. However, we quickly realized that we didn't want her to be driving a car that could carry that many people…not worth it. Get a nice car for yourself and then see what happens in a few years. As long as your kids are responsible having an additional driver in the family is always a nice and convenient thing to have.