I had this same problem when I was younger. I lived on a farm and I started to learn to drive big trucks when I was 13 and I was terrified! But one day my dad took me out into the middle of nowhere and just let me have at it. It's easier to learn to drive when there isn't anything to run into and no one to hurt and then he just kept taking me to more and more populated places each time. Eventually I became a heavy equipment operator for the navy. Haha crazy right! My point is start small. Get comfortable with a car before jumping on a highway. Good luck!