I am thinking, (guessing) - 125# lady - 250# BG - could well legitimately have her genuinely fearing for her life. If that bad, her gun could well be brought into play.
Much would depend naturally on her perception of the threat, the way a BG talks, moves etc, and even her options for taking flight (top choice usually). Sure, some training programs could well help her with threat assessment, as they could us all.
In the final analysis she like anyone, would have to ''play it as they see it'' - hopefully being able to later justify the actions taken - a situation any of us might encounter.