abusive parent has control of my college fund, what can i do?

this is a weird one but i feel like i’m in way over my head and would appreciate any advice.

i’m 24 years old, and i’ve had a college fund in my name since i was a baby. i didn’t go to college and i don’t think i will. i thought my abusive mother spent it all on scientology programs when i was a teenager, but recently my little sister, who still lives with my parents, told me there’s still a good chunk of money left. my mother is hiding it from me because i’m transgender and she wants to stop me from getting any medical procedures done by any means necessary. she does not care that i’m struggling to pay for rent, food, and medication for my chronic illness and could really use the money to survive. i want to get the account out of her hands so i can finally cut ties with her, but i’m afraid that if she finds out my sister told me she’ll hurt her. i don’t know much about this sort of thing and i’d love to know what information i need, what questions i should be asking, if i have any legal ground to stand on for getting my money back without getting my sister in trouble.

i’m sorry if this isn’t the right subreddit for this, if that’s the case i’d appreciate being pointed in the right direction.