Hey Shannon,
I read your thread and thought I would suggest maybe telling your parents with your sister. Additionally, rather than tell them you smoke weed maybe you could rephrase it a little and tell them you are trying to quit. It also might ease their minds to know you don't buy or sell or anything of that nature. When I told my mom she didn't even care but she grew up smoking weed and didn't see it as a problem as long as it didn't effect my grades. Maybe letting them know that you won't let it get in the way of your future and you don't plan on ever doing any other drugs would help settle their minds. I wish you the best of luck. Tell me how everything goes with telling them and with quitting. I am always here if you need someone to talk to. Take care and stay strong.

Lots of love <3 Mimi