I just got my permit and one of my 18 year old friends said he would teach me how to drive. Can he do that? Am I allowed to drive with an 18 year old or do they have to be 21?

Check out the graduated driver's license laws on this site. According to A.R.S. § 28-3154, an Arizona driver with a permit can drive on the public highways for twelve months when both of the following requirements are met:

1. The permittee (the person with the permit) has the permit in his or her immediate possession AND
2. The permittee (the person with the permit) is with awho has a class A, B, C or D license, who is at least twenty-one years of age and who is in the seat beside the permittee.