You may have to talk to your mother and tell her about the specific boundaries that you don’t want her to cross.
Let her know that these boundaries are not negotiable.
If she continues to gaslight you, you may need to call her out on it and tell her that you will not tolerate that kind of behavior.
In essence you have to stand up for yourself.
She has gotten too used to having it her own way.
Once you show her that you are very serious and not relenting, she may ultimately decide to start respecting your boundaries.