AITA for “erasing” my parents after my cousin stole my food and had an allergic reaction?

I’m 16f and a couple months ago my parents cleared out their office room so my 13 year old cousin could move in. Ever since she got here, stuff from my room has been going missing. Mostly clothes and my braiding hair since i do hair on myself and others..my crop tops, tube tops, little things like that kept turning up missing or when i did find them they we’re cut shorter or stained. Important detail: no one in the house has a lock on their door except my parents and obviously the front door.

I asked my parents for a lock since it was pretty clear who was taking my stuff, and they said no because a couple months ago I got caught smoking weed and they “don’t want anything happening in my room.” Okay cool, i understood that but not the fact that my things were getting stolen and nobody cared but me since i’ve brung it to they’re attention many times but her actions we’re always excused with “she’s growing up and finding herself, let her be.”

So one day I confronted my cousin and was like “if you wanted to borrow my stuff you could’ve just asked, I probably would’ve let you.” And she literally said “because it looks better if it’s stolen.” We argued, parents got involved, and got yelled at since I’m immature for arguing with a 13 year old (who obviously knew what she was doing.) After that, my parents started acting super standoff-ish with me. Like barely talking, ignoring me in the house, weird passive-aggressive energy. I was basically just staying in my room to avoid everyone.

Fast forward two weeks. I come home from school and immediately get screamed at by both my parents at once for giving my cousin food poisoning. Turns out she went into the fridge, stole my leftover peanut noodles (which she 100% KNEW were mine and that she’s allergic to), ate them, and had a reaction. Here’s the thing though..nobody in the house even knew she was allergic to peanuts except her and my dad. Not me, not my mom, no one else.

Somehow this was still my fault, OKAY COOL.

My parents said i could stay with my grandmother who lives 36 hours for the summer for my cousin to “calm down” from the situation since every time i walked around in the house i’ve lived in for sixteen straight years she complained she was scared of me.

i’ve been here for a week or two.

I tried checking in with my parents a couple times but they barely answered, so I just blocked them, now trying to protect my peace and live my life without the title ”the food poisoner” sticking on my back. Now they’re blowing up my grandma saying I’m trying to “erase them from my life.”

And honestly…i‘m not, i’m just tired of putting in effort in a relationship they have obviously given up on, AITAH? (please give feedback and or advice)