<human>: Can you provide a brief overview of the text?

She's a good kid that's done well in school but I think maybe peer pressure is starting to get to her a little bit. She recently posted a video to Instagram where she was smoking pot and making out with a female friend.

Both of these things don't bother me morally. I've never smoked or drank alcohol by choice, my wife smoked once years ago and didn't like it so she hasn't ever again. My sister is 18, she's an adult and can do these if she pleases. However, my parents were and still are very conservative. I have ratted her out to them before when she solicited my wife to buy alcohol for her and her friends a couple years ago, due simply to the ramifications of my wife being caught had she decided to do so. Her punishment was being "grounded" for "two weeks", which was actually more like 1 day. I will admit that it does kind of rub me the wrong way that I was the child that would be severely punished for acting like she does, while she gets off scott free. I know that's just a little immaturity coming out in me, it's not rational to feel that way.

Caveat: The part that I personally take issue with is if she continues to smoke pot and wants to be around my newborn son. I plan on talking to her personally if the behavior continues. She would not be allowed to be around my son alone if that's the case.

I just want to make sure my judgement is still pointing north, in this case.
<bot>: 18 y/o sister lives with my parents, posted video to Instagram smoking pot and kissing a female friend. Should I tell my parents or leave them out of it since she's legally an adult?