@mjkobe You are a PUSHOVER
This is called a passive parenting style and it is associated with long term negative outcomes.
Read about authoritative parenting. Get effing consistent or you are going to be sending her down a terrible road that possibly results in narcissism and hedonism. Where does that go? Could go any direction. She's 12 and you're letting her go to parties when she isn't even responsible enough to ride in a freaking car?
Time for tough love.
Do everything you can now to check the boxes you're supposed to check so you don't get forced into a realization that her inability to adult, her teen pregnancy, drug experimentation etc is your fault.
If you continue to give her what she wants when she acts like a brat you are providing her dopamine rewards for crappy behavior and IT WILL NOT STOP.
Switch it up and be prepared for a rough 6-12 months.
Also take her ass to therapy and get some for yourself.
Sorry you're going through this. I know it's heartbreaking, overwhelming, and hard.
But think about how much worse it could get if you don't figure out how to provide her structure and love her with authority.
Be there for her, don't abandon her, but also don't take her crap at all. You are the adult.
She'll thank you when she's 30 if you play your cards right here. You have the power, take it. Do not let a child run your household and run your and her mental health permanently into the ground.
What happens down the road? Are you prepared to take her the hospital? Call the police on your child? Send her to military school? Alternative school?
If you let this get out of control you will lose your options and those will be the options you are left with. You don't want to have to pick any of them, ever. Don't put yourself in that position in 1-2-3-4-5 years down the line.
Also, look for a youth crisis hotline in your area.
When you finally put your foot down she is going to lose her mind and that's when you call them and they will come and stabilize your household. It is not CPS or anything like it, so fear not. There will be resources to help your family somewhere.
If you want more specific advice about accessing resources DM me.
I have used them.
Also, you need bonding time. On your terms. But quality time with her will help offset her harsh feelings. She can't go to the party, but she can watch a movie with you at home that you pick.
Edit
Consequence example:
Find what matters to her, say her phone, and lock it in a box until she earns it back. Yes, get one of those fireproof lock boxes.
No amount of hemming, hawing, or fit throwing should put that phone or laptop back in her hands. Only respect to you, shown consistently over the course of 2+ days. Every time she disrespects you, the 2 days until she gets her phone back starts over.
She goes out of control? Cool, I'll throw away the key and you can start working for money to buy yourself a new phone, even if it takes 6 months.
Alternatively, drive the phone to Grandma's house. Leave it there.
We'll only go get it when you have changed your behavior. Same system, alternative to spending money on a lock box.
Give her more responsibilities. You want to act like an adult? You're responsible for cooking the family dinner 3 nights a week, if you eat it or not.
You're going to weed outside. You're going to have responsibilities beyond cleaning up after yourself to help our household, because you are taking a lot more energy and time with your outbursts than you are contributing. You are taking wellness from our home so you're going to work to put it back.