I need to vent

Everyone in my family is acting like I’m not allowed to worry about my sister; she drives my dads car off in the middle of the night and gets in trouble. Her punishment is being locked outside of the house for the day, she is 16 and all of her friends live within 3 blocks, she was supposed to come home at 9 but didn’t show up until the next morning. So at night I texted 3 of her friends and played it cool like ‘oh yeah the parents are asleep and she doesn’t answer my texts, is she with you? I want to say something to her’. She got mad and so did my parents because apparently I’m not allowed to worry because she’s older than me. Two weeks later and one of her friends decided to break the friendship and she’s blaming me because of the texts. But the only way her friend got the information is because my cousin is also the friend’s friend, and since she gossiped about it saying my sister was drunk or something I’m getting the blame because I got worried about my sibling. Sorry I had to vent somewhere my family won’t see it.