She posted before she was driving down to put someonenin hospital
The prosecution will certainly use this to paint a picture of her as a violent person. But a vague, unspecified threat amidst social media 'beef' isn't necessarily evidence that she'd made specific plans to end the victim's life.
the grey bit will be the fighting before
They defense may use the fight to claim that the defendant was in fear of her life, drunk and not thinking clearly, got in the car for safety and was attempting to flee with tragic consequences.