Sounds like your grandmother is a very old-fashioned.  O.K. so that's not it at all.  She is probably upset because your not the innocent little girl you used to be. I can say this... You must reach her no matter what it takes. Tell her that you love her but, if she had knocked, this would not be an issue,   that it breaks your heart that she won't even talk to you about it.  This could cause her to worry, or stew, herself into a heart attack or a stroke. So do what ever it takes.  I'm feeling grandma's pain....I am one too.