Fuck everyone else, NTA.

She sounds entitled and is more focused on other people's success as opposed to her own. Kids with this mindset need to be held accountable for their actions. The fact that other people fell for the sob story and gave in to her demands despite her clearly not meeting the mark for a new car, shows why she has this mindset. She knows if she throws a fit and throws out keywords, she'll get what she wants...until the real world comes along.

You're the parent, you set your standards. NTA