Hence why I (and any family I'm blessed with down the line) train in Jiu-Jitsu. The amount of confidence it engenders is insane, but you can also back that up with the knowledge you can likely defend yourself in a huge range of scenarios.
As far as the school incident here is concerned, this is indicative of the endemic issue of schools protecting bullies. The fact anyone thinks the girl went too far in that situation is disturbing. Frankly, I hope she straight up ruined at least one of them.
Props to her regardless.