Well, when it comes to drugs, I can't tell you how many people think they are knowledgable on the subject. There are bad drugs, but to be honest, addiction to soda can be just as bad as drugs.
I have been taking opioids for the past 7 years and medical marijuana for the past 8 months. At first, I was so worried that I would become addicted to the stuff and worried about what was going to happen. I've learned that
Everyone seems to be a know it all and
Most people don't really know what they are talking about.
It's mostly hearsay and what they've seen on the telly.
Drug addiction is a person who is running from something or away from something. It so much a mental thing. Marijuana being a gateway drug, as were taught, is a mental thing as well, but it's BS. Marijuana, other than smoking it, has a lot of healthy benefits. Now, if someone is chasing a high, it doesn't matter what they start with, the issue is already there. It's a mental thing. They are trying to get rid of something or cover something or escape something. I don't get a high from my medication or a release. I did get horribly dizzy when I changed prescriptions once, but what I'm trying to say is that all of this most likely hinges on something needing to be addressed at the mental level.
Figuring out the "why" would be the first thing to address. Find out why she needs this. No matter the debate about how good or bad it is for you, focus on the why. Is she unhappy? Is she needing someone to lean on? Is it a peer pressure thing? Talk to her in a very non-judgemental way. Don't be her judge; be her friend. Let her know that you care and that you are there for her. Although your parents may be wound a bit tight about this, try to understand what it means to her. The legality is a problem. Let her know, in a very caring way, that this is affecting you and it's putting you in a tough spot, but that you do care. Stress the fact that you care. The biggest thing in this world, whether people want to act like its not, people want other people to care and they don't want to be judged. Being a judge just pushes everyone away and doesn't help the person.
By the way, the comment about marijuana being illegal in Colorado on the federal level overrides the state level... The only way that affects you is if you do something like try to get a federal job, buying a gun, or anything that would need to involve the federal government; otherwise, the use of marijuana in Colorado won't affect you legally. Check this out for an explanation.
Check with your sister and let her know you care. Try to find her reason for it and let her know that you will be there for her. If she gets caught by your parents, ask her to keep you out of it and not use your being there for her as support to your parents' argument.
If busted and your parents jump on you, ask them if you can talk to them like an adult. Ask them if they would out their sister or brother and let them know that you feel trapped. When they are gone, you and your sister will rely on each other and trust will be an issue. Let your parents know that this is a hardship for you as well.
Find out if your sister would be willing to injest it any other way that doesn't involve inhaling smoke. That's what would hurt her. You are in a tough spot, but don't beat yourself up over it. Know that you are doing your best and frankly take a stand whenever a stand needs to be taken.