Im a minor, and have my own car. Mother refuses to hand over my key. what are my rights?

I'm 17, and I own my own car. Its fully paid off. I own it outright. it's titled and registered to me only. earlier today I misplaced my car key, and spoke with my grandma about what to do. and she told me that my mother had a spare key. which I didn’t know about. so, I called and asked her for the key. I told her I probably locked it in the trunk, and when she got home she unlocked the car for me but it wasn’t there. long story short is that she adamantly –refuses- to give me the spare key, and i'm literally unable to get into my car when I want or need to. I know that if I were an adult, she’s completely in the wrong, but im only 17. can she refuse to hand over the spare? She is in no way related to my car, the title, or registration. I don’t want to get the police or anybody like that involved but she is absolutely ridiculous and will not hand it over. I cant use my car at all, and this is just a joke. It’s a base Milan, and the key is the only way to get in. ive been at her for about 2 hours now demanding my key, and it is absolutely impossible for me to get it unless I were to get violent. and im not that stupid.