It really depends on the school! Each has its own regulations For in state tuition. I would go to the financial aid website at your school, they should have a document there about establishing residency.
For me I have to live there and work there for at least a year prior to school starting to establish residency. they do not change residency status after your first year in the program unless you have been working. So having an address there, changing drivers license, and registering the car in the state are all not enough to establish residency. Maybe your school is easier.