I was straight edge most my life. So when it came down to telling my parents that i started to smoke. they werent happy. But after a while, since they noticed my life was still going in the right track, they kind of just never brought it up. they know i use it mainly as a medicine. even though they dont believe how if could be. Im an adult as well and they have to get over it. I smoke pot. I dont drink (my extended family are alcoholics, minus my parents) so thats a plus. and i havent done addictive drugs, and no longer use psychodelics. I would think if your an adult. That they should be fine with it or get over it quick... But if your a kid. Im sure they want to look out for your future in adult hood. and protect your lungs. Good luck! do it, i recomend you tell them, its good to just let it be out there, keeping secrets suck.