Even though abuse is unpredictable, it is still scarring.
Please know that that there are a lot of people who wish to help you.
I seem to recall reading something somewhere that because you are a very good student with good grades, you are more likely to benefit from outside help, and are more likely to become a success story. If you were as dumb and stupid as your vicious mother complains, then you would be less likely to benefit from assistance.
Plenty of parents yell at their kids - lord knows I have raised my voice at my pups more than any of us would have liked. But everyone would agree that garden vanilla yelling is different than hair pulling, punching, and beating with a hanger. You need and deserve help.
As much as it pains me to suggest, I think your mom and dad both need help as well. And this is far more important to your long term future than your SAT scores.
Also, please understand that the vicious words themselves are abusive. Even if your mom calms down, and even if she apologizes - whether or not that is part of her pattern - you have been abused and need to take steps to prevent it recurring - you need to protect yourself.
Getting help does not mean your mom or dad goes to jail - it means that you get protected. Parents are rarely prosecuted for abuse even when reported - sometimes rights are terminated, but more commonly a child social worker and family services will step in to try to protect the child. We know this is not easy.
Please please get help, for everyone’s sake. Even if your mom gets angry in the short term, over time you all will likely agree that getting help was the best choice you had.
Whatever the family dynamic currently entails is not working. So it needs to be fixed. But before that can happen, you need to be protected.
Please let us know how things work out.