State of residence for application?

Pretty confused on this, as there is a lot of information out there. I was born and raised in Oklahoma, my drivers license and technical permanent domicile on taxes and things like that is there. I moved to southern Missouri for college, then moved in April to Kansas City Missouri for a gap year. I possibly have the opportunity to move somewhere else in the area, and know it would be more beneficial to be on the Kansas side. I also work on the Kansas side. Can someone explain where my state of residence would be per AAMC, and if it would be beneficial to claim residence somewhere other than Oklahoma? I’ve heard people say you have to live in an area a certain amount of time prior to claiming residence, and others say it just has to be changed by application date. Thank you!