I'm going to ghost/ignore my sister after she revealed a secret of mine to our parents
I'm sorry about that. Would you mind saying what did she reveal to your parents?
The time that I was drunk at a party. I told her what I did to one of the arts works inside the museum.
I understand why you are upset, it's bad that your sister revealed your secret. She should have kept your secret. However, you should communicate with her to tell her what she did was wrong, instead of completely ghosting her.
I'm going to ghost/ignore her forever.
I am afraid that she may miss you and she may long for the relationship you had. I agree that she made a mistake, but she may be willing to change and make up with you, and you ghosting her restricts her from making it up to you.