Ohio has a "Stand Your Ground" law.
Those girls threatened shorty, showed up to her house, and physically assaulted her.
Under Ohio "Stand Your Ground" laws, shorty was in her legal rights to defend herself by lethal means if she felt she was threatened.
There's no stipulation in Ohio's law that force has to be met with equal force, and you can use deadly force to remove yourself from the threat.
That law was written for white boys, but if it's on the books, it applies to shorty too.
With all that being said, I'm not condoning one young black girl even attempting to kill another young black girl, even in self defense, unless absolutely necessary.
But, if we're going to go by law, as it's written in the state of Ohio, according to the limited video evidence of the entire situation, that young lady was acting in accordance with the law by defending herself against someone that stated a threat, showed up to her home, and assaulted her. (Before y'all say, "she should've stayed in the house!", Ohio's law also stipulates that you don't have to retreat from the threat).
She even alerted the police first, which is not a requirement in Ohio's "Stand Your Ground" laws, so she went above and beyond to protect herself from the threat.
At that point, according to the state of Ohio, you can defend yourself, even by lethal force, and you're within your legal rights as a citizen of the state.
That's Ohio law, like it or not.