If she is embarrassed due to what stangers think of her in your car, let her go.
You see you and what she chooses, (you) should come frist, not nobodys.
This is very important.
I can see complaining about stinking, dirt and stuff, but not what others she dose not even know being more inportant than you, and what you have accoplished.
Heed my words. YOU should be more important than strangers.