Billie Jean would have been killed
When Mr Pyatt is shot it's to the shoulder and Billie Jean's head is in direct line of the bullet behind him. I've often noticed this, among other movies where other people would have died, and wondered why the director didn't have her crouching down considering her brother is blindly pointing a gun everywhere even at his own face.
Then again she was stupid enough to go in the store alone, demand money from the father of a sociopath and even follow him upstairs.
Generally kids from a trailer are more streetwise than this.