If your grandmother knows, maybe you could bring her with you to talk to your mom, just for support.
That's a good idea.
Bring someone else who knows and you trust for emotional support if you are scared
Get grandma to tell her.
Why are you scared?
Do you have the ability to talk to a consular?
Perhaps if you can't say it you could write it in a letter.Tell her you are afraid.I hope you get the response you need.
You have no reason to fear telling your mother. Being raped, no matter the context, is not the victims fault, and if she is in the least bit intelligent, she will understand.
Listen dear, you are just a person, and things happen to people. Your mother is a person as well and she should understand that there are somethings in life that are uncontrollable. As a mother, and a human being, she should be there for you, because you were the victim.
tell her to tell your mom for you, or be with you when you tell her