I was a bit scared when I had my learners permit. Terrified at times. I live in the Los Angeles area, people are f*cking crazy drivers here (much like what TEoS describes), on top of that it's very much a car culture here. Most people commute 20 miles or more to work, and sometimes spend hours a day inside their car, their car is their life, and they get very aggressive while in it. It's intimidating. But you have to just get in that car, and drive. The more you drive the more comfortable you get.
Also, drivers tests are very intimidating, but it's really no big deal. Just drive. 9/10 everyone does the right thing in any given situation while driving. And even if you do that one thing that you do wrong, unless it endangers someone, the tester will shrug it off.
It helped a lot when I was young thinking about all the really stupid people I know that have a driver's license. There are some f*cking morons that are licensed to drive. Complete f*cking brain dead morons. And they drive, and they don't crash. They get around, and everyone is safe.