Mom treats me like I'm the same person I was 30 yrs ago.

Dean, I am a mother of a son who got in a lot of trouble with alcohol and drugs when he was young, 30 yrs ago, and for so very long I was afraid of answering the phone for finding out he was arrested again or dead. He has relapsed a few times over the years, but for the most part remained sober. I don't always suspect him of returning to the past and have done my time in learning about addiction and how to treat him with respect. Still, I sometimes panic when there seems, from something he's said or done, that he's drinking again. I suppose it's some sort of post traumatic stress disorder for me. I do not have dementia, not yet anyway, and I have these feelings, but can catch myself from words or actions that would be disrespectful to him. So your mom with dementia, as others are telling you, will not have the capacity to remain in the present and therefore see the you as the you were long ago, and act accordingly. I think if you remain calm and just tell her No I don't do that anymore, she will at least in the moment behave herself. Unfortunately, you will have to do this over and over and over until you think you can't stand it any longer because she won't remember, but it most likely will get easier for you. I do think for your own personal mental health it is important to make some sort of statement of protection for yourself. You shouldn't confuse her too much with saying it was 30 years ago, though. She's lost in time. Go with her to that long ago time, but be the person who got out of the horrible cycle of addiction, and tell her you've changed. Tell her that for your own sake, even if it sticks in her brain for only a minute.

Your mom has dementia
So in her mind you just might still be that person.
YOU know you are changed. YOU know you are a better person.
If it gets to the point where this is an issue if you are the primary caregiver you may have to get help in just to save yourself from the anger and frustration. Sometimes stepping back so you are not in the direct line of fire needs to happen.

A few difficult things...
Don't argue with her. You will never "win" an argument with a person that has dementia. Redirect if possible.
If it gets a bit much, walk out of the room (if it is safe to do so)
Wear headphones, earbuds (again if it is safe to do so, sometimes you have to hear what is going on)

I put boundaries down with my mom to not say things to me that hurt. I'm dyslexic and I was always the joke of the family. So now when she tries to poke fun of me I say, it's not nice to poke fun of the learning disabled.

She doesn't say them, but I see her catching herself, so I know she is thinking them. And that hurts too.

So I'm not sure the answer.

Just be sure in yourself, you have done a great job on your sobriety , be proud of who you are and who you have become.

Are moms are not going to learn at this age , that what they are saying is wrong

Your profile says that your mom has dementia, so as you should already know, folks with dementia lose their short term memories first, but retain their long term memories.
So the fact that your mom is remembering her long term memories of you should be of no surprise to you, as that is all she can remember.
So I guess at this point all you can do is show her with your actions that you have changed and not take anything she says or does so personal, as it is now the disease talking and not your mom.
And if it gets to be too much for you to handle, you may just have to step away and let others do the caring for her and you can just check in with her periodically. as you don't want anything jeopardizing your sobriety.

Congratulations on your sobriety. Has your Mom been treating you like that all along? Or is it a recent change? I agree with others that dementia and short-term memory impairment will prevent you from having reasoned and logical discussions with her, or anything that requires her to retain new information. When your Mom treats you inappropriately you just have your boundary ready by changing the subject, distracting her or walking away. She can't help it... her brain is broken. You know you're a changed person, and so does God, and that's all that counts.

Your mother suffers from dementia so you trying to change her memories is an excerise in futility. She cannot retain new information either, so just let her words go in one ear and out the other. Hire help with moms money to give you respite from the frustration as needed.

Best of luck to you.

Have you sat down without being accusatory and discussed this with Mom?
Gently.
It would be perhaps something started off with : "Mom, I realize that the "me " of twenty years ago was really a tough thing for you to have to live through. I know you have known how hard I have worked to change. Can you tell me if you recognize and approve of the changes? And can you tell me where I still need work"?

This leaves it open to your getting/wanting HELP from her.
Listen; don't argue.
Ask for specifics in your behavior that still trouble her.

Or, if it's easier, take the advice I so often give here, which is to move 1,000 miles away from mom.