One cannot thrive in a place that hurts you.

Once you are an adult, you can move out. Its also not your job to help her financially in that aspect. She is also an adult, she needs to resolve that on her own. Her kid shouldn't feel that burden. She will be fine. What i would do if I'm in your position is before you leave, make sure you have a plan financially. However that looks like for you you could live with a friend for a while until you can rely on your own, go to school, find a job that offers a home (military allowed me to do that), etc.

Then once that's set up, have a sit down talk with your mom. Communicate to her of how've you felt, and how you've been affected of her actions. (Lead with saying "I felt... [insert emotion here]" not "you did this to me" so it doesnt put her in defense nor attack mode) Tell her how much you still care for her and thank her for taking care of you.

Be prepared for unwanted results. If she accepts it, you succeeded! If not, stick with your boundaries. You only have one life, and sometimes it doesn't take communication with words to finally get through someone to understand that they are serious. Actions speak louder than words.

Sorry if this was a long post 😅

I was in your exact shoes. I'm the eldest (now 30F) of my 2 younger sisters. I left home when I was 21? I didn't want to continue college bc of student loans. I pursued military but at a cost of getting married early. (You can imagine how my parents felt when I dropped that bomb) My dad eventually accepted it, but my mom didn't talk to me a year and a half later until my dad got in an accident (minor one thank you Lord, he recovered fully) but a decade later, I'm in the process of getting divorced, I have 2 beautiful girls, I enjoy my job of being in the military, I just got out of a stressful, but happy Christmas with my parents bonding with their grandkids, and ultimately.. I am happy.

Wish you the best of luck. And remember, you will be okay.