Do I have to take this to court?

I'm 16. My dad and mom have joint custody. Dad in TN, Mom in OK! I'm in TN but been living with my Gma for past two months. Lived with my Mom right before then. I wanna go back to my moms. I know at 16 I have the right to choose who I wanna live with. Again I don't even live with my Dad but yet he wants to try and stop me. I don't get it, but anyways do I have to take it to court or what? Who do I talk to?