This is not likely to change if your mother is in this much of denial. I suggest you work a plan “B”, which is that you need to get out. This isn’t letting it go—it is letting you grow.
Instead of beating your head against the proverbial wall of your mother, start to put your energy into your own well-being and individuation. It is time for you to make the break and find alternate living arrangements. You list your age as 29 and while I can understand the school and financial restrictions your effort should be on improving those resources and living arrangements rather than stay in a highly toxic and counterproductive environment. It isn’t your job to change your mother. It’s your job to take good care of yourself in spite of her behavior. It is time to make the break.
Wishing you patience and peace,
Proof Positive Blog @ PsychCentral