Childhood aside- my parents are screwing me up in the present. My father less so- so i'll skip in this little spiel. He's just mentioned as the not one to turn to and not helping with my emotional rollar coaster.

Ok the circumstances are: I live alone in an apartment paid by my grandmother about an hour away from my mother and step-father. I understand the whole mothering thing- but when i was growing up my mom wasn't really a mom to me in the traditional sense. But now she is trying to be which is making me angry. And every time i talk to her we are getting in arguments over things which i don't consider her business (since i live alone) or she is belittling/humiliating me about what i love.
The example situation which was this last saturday. i play on her adult softball team and after the game most of us went out to this fast food place- well i was bored since i don't fit in their age group (by like a decade) so i was doodeling on napkins. a member of the team (she's a like a grandma) looks across the table and says "Oh how cute! I wish i could just sit down and draw like that." to which my mom cuts in with (all straight laced and frowning) "It's anime, it doesn't count." Super awkward- to the fact my own mother just "dissed" me in public in front of people we know and i have to see again next week. I wasn't hurting anyone and there ya go.
Anyway besides that she does it constantly where she cuts me down for what i do (mostly hobbies: art, anime, writing, reading)- I honest to god think she is starting to go through menopause and i tried talking to her about it and she bit my head off.
I have my own mental problems that i am fighting- and talking to my mom sets me back to the dark side (in lamest terms)-- is it understandable to want to basically cut my mom from the 90% out of my life?

If your mother is trying to amend for not being totally mother-like when you were younger, you should let her. Some good might come out of it. It sucks that it didn't happen when you were younger, when you need it the most, but you need to set that aside.

Sit her down, as if you were treating her like a real mother, and discuss the things you like, and how it hurts you when she puts you down when you're doing the things that make you happy. If she wants to be a good mother, she needs to respect this. And is retrospect, you need to respect her as well, this can't be one sided. Trying to bring back a positive connection with a parents is really difficult, but only good can come out of it. And I believe you should be a little open with your mother. Yeah, you live alone, but that doesn't mean everything isn't your mothers business anymore, it just means you should be responsible enough to take reasonable action when needed.

Ugh, I know how it is. It's even worse for me 'cause my mother was like, NEVER there and then decides to show up here & there between when I was 16 up to now & she's trying to be a mother. No. Not when I'm already grown up & in my own mind set.

I've had ambitions to tell her to shut the hell up. I kinda did once & she kinda beat me up. So next time I won't have my guard down about her & she'll get hers.