I started driving when I was 4 1/2 years old. My cousin had 400 acres of land, and we saved up our money and bought a beater car from the junkyard to drive around in. Started on public roads when I was about 6-7 years old. I got my permit when I was 15, which allowed me to drive with anyone over the age of 18 that was licensed in the state of Missouri. Got my drivers license when I was 16, which allowed me to drive with anyone, at anytime.
If you haven't driven before, I suggest you find someone that will let you practice in their vehicle. My girlfriend tried taking her test without prior driving experience and she failed the driving exam, but passed with written. Read the handbook, thoroughly, because you will have both a written exam, and a driving exam. If you fail the written exam, you can't proceed to the driving exam.