Most Helpful Girl
Complete overreaction, and based on that alone I can understand why the mum has done what she has.
Don't pay her any mind. Tell her you won't be spoken to like that and not to communicate unless she can be a decent human being. What a horrible thing to say
Most Helpful Guy
1. Don't die in a car crash.
2. I'm sure her mother has a reason for putting all of this is writing. Probably, they have discussed this before and your girlfriend denied having said that she would agree to certain conditions. Parents want to hep their children beyond age 18 but they don't want to be used. There is at least one more side to this story.
3. It would be a mistake to try to intervene in the conflict between your girlfriend and her mother.
4. It sounds as of your girlfriend is not yet willing to accept adult responsibilities and that is a WARNING SIGN!
5. If your girlfriend thinks that her stress justifies saying something horrible to you, she does not respect you or your relationship. You will probably be looking for another girlfriend in the near future.