Merry-juana

I got busted by my grandmother and she is stressed as hell right now. I know there is no way to convince her pot is ok but is their anything that can help me convince her that it is my decision and I will not make her accountable for it. She is probably not going to do much to me, but I just want some peace in the house, and I want her off my back. She is worried because I am the third child she raised to become a pot smoker, and the other two pretty much fucked up there lives and she thinks it is because of the pot, I just want her to stop worrying and screaming, my grandfather won't be able to handle the stress.

Edit: Now I think she might actually do something bad, I do not know what but I have to figure out what I am going to do. Also, how long do you think it will take for her to get used to me smoking, if at all?