Really, what your sister does is her business, and what you do is your business. I would guess your parents didnt do the best job of raising independent kids, because your sister is caught up with this rebel, and uou are so worried about following the rules. I was once in your situation, with an older sibling going against the rules and taking all my parents attention. I felt as if i had to be super-good to make up for his badness. That is a very unfortunate position to be in, because frankly my parents didnt care about what i did. If i were you, i would think very carefully about what i wanted for myself in my own life, then try to succeed at that. Sincerely.