I believe you have to show proof of residency after a year. So if you get an apartment or something, you may be eligible to apply for in-state tuition by showing proof that you live in that state via bills, mortgage, mail, etc. I don't know if it applies to ALL the public schools. I would check each school individually as some of them may have different processes and time requirements. I'm not sure if it's possible for international students but I don't see why it would be any different from a student coming from a different state. Both of you would be living there the same amount of time. When in doubt though, just email the school! They'd be more than willing to help explain!
