I'm 18, why is my mother still like this?

Long story short, I got kicked out of my parent's house and moved to my grandma's in the city for a whole TWO months. I got a job, I bought my own things, I did what I wanted, I did my own laundry etc... My Dad asked me to reconsider coming back home, over and over again I told him I'm not going back unless you guys accept I'm used to the lifestyle I was living. So I moved back after my Dad asked me about four times, but now my mother is being a tyrant yet again. How do I make her realize, I honestly don't give two shits about what she has to say? And if she disagrees or makes my life harder that I'm just going to move out again? I already have luggage packed incase I can't take her bullshit anymore.