In the moment, with everyone and everthing going on around her, I doubt she was thinking rationally or even knew that torching a car would be a long prison sentence. (if someone asked me before reading this article, I would have assumed a large fine + some community service maybe; then again I am not American so I have no idea how sentences compare).
"Everyone else was doing it" didn't fly with my mom, and probably won't get a pass from Judge Wapner, either.
Anybody thinking of going outside and playing anarchist should know what they're getting themselves into, wait until your cellmate tells you that they're getting out in 2 months and you have to hold their contraband and weapons or the guards decide to put you in a high security yard because you're in there for something ridiculous like 'terroristic threats and arson'. You don't ever get out on schedule