The car thing was dumb
So she goes and asks her parents if they still have her old car without even trying to start her mini cooper? At the end of the movie she just drives off in the mini cooper so obviously it wasn't damaged so badly that it couldn't be driven.
Nobody would have a 15 year old car just sitting around, except for some rednecks, but once they let the car sit that long it stops running, and they never get around to fixing it. So even if they did still have the car, it wouldn't work.