AITA for telling my grandma to respect my privacy?

So for context me (17F) don’t have a dad and I been living with my grandparents bc my mom isn’t emotionally available, this led to my grandma to start taking care of me since I was 2. Recently I have been diagnose with pre-diabetes and I was super scared I didn’t wanna tell anyone. The way I found out made me super mad, my grandma went for my results to the lab and I didn’t even knew about it, for me the right thing was to wait for me to get back from school and open my results together but she had other plans. I went to a party and when I got back she suddenly says “hey glad you’re back, don’t get scared but you may have pre-diabetes” I was like what ? Keep in mind I just returned from a party I was sober but I had like a shot. The next day was family day and my aunt comes and sits next to me she says “how do you feel about it ?” I was confused because I didn’t knew what she was taking about. Then it hit me I said “who told you ?” She said “grandma” I was okay with this because I love her and said okay but i don’t want my mom to know she will make me feel bad. Then my mom comes out of nowhere and starts saying she already knew and that I was a terrible daughter for not wanting to tell her, I obviously didn’t say anything and she went away as usual, then my aunt said “I came here to talk because your mom’s boyfriend and grandpa are talking about it” I was super furious so I went and talk to my grandma about it, I told her “you should be ventilating everything to everyone, you shouldn’t even had to open those results.” She got mad at me and told me I was wrong and that family was family and I should be okay with her telling it. She knows why I’m not confortable about it. (They usually make comments about my appearance and how I’m never skinny enough) I also had eating disorders and the worst part is that she is the one that tells me to not say anything to my friends. So IATA ?