Question: I am only working about 4-6 hrs a day and my employer is demanding that I take a 30 min break while on my shift is this legal.
In Arizona there are no laws or regulations covering breaks and lunch hours either for adults or children of a certain age. There are federal labor laws that cover breaks and meal times. Generally, if an employer does give breaks, then the break must be at least 30 minutes for the employer to be able to deduct the time from an employee's pay.
See LawForKids.org answer 18375 for more information on breaks at work.