I recently found out (accidentally, when I was looking for something in her bag) that my eighteen year old sister has condoms and hemp paper to roll up hemp idk. So she's having sex and smoking whatever, which is not okay in our family. I feel as if I don't know her anymore and that maybe she would have told me (we're two years apart).  Should I inform my parents of what she is doing so they can put a stop to it and potential problems in the future?