Hi Op

My advice to you, is that you work very hard on not taking responsibility for your mothers choices. You do not have to manage her decissions, nor do you have to discuss them with her beyond stating your opinions. It is enough to tell her the reasons why you think this is a bad idea. Whatever happens, you have made her aware of your position. It is beyond your control wether she considers your boundaries firm, or malleable. The best thing you can do, is stop preoccupying yourself with matters beyond your control, and trust in your ability to mean NO when you say NO, and perhaps if that is an issue for you see a therapist to learn how to rest easier trusting yourself to uphold your boundaries with your mother.

You can ofcourse justify your positions with the practicalities regarding your move etc, but I do not subscribe to the belief that you owe those kinds of explanations to validate your stance. Rest easy in yourself, believe you are not your mothers keeper and tell her so in a calm and easy manner. Making your mother understand that she is on her own with her decission is all you have to do. Doing so without justifying yourself is hard if you are used to having to do so to feel ok with your choices.