Enrolling at an Indiana public college or university within 12 months of an honorable discharge gets you the in-state tuition rate even if you are not an Indiana resident. Within a year of enrolling you have to start establishing Indiana residency.
Ask the admissions or registrar office at the Indiana public college or university you are attending to apply the resident tuition rate, and show your discharge paperwork.
Your DD214 showing an honorable discharge within the last 12 months, and later evidence that you are establishing Indiana residency.