What should I do about my secretive younger sister?

[hamid]

Find a time that she have nothing to do and in a good mood.You need to confront her as a best friend before a big sister, let here know that you are the only one that knows about it and you won't tell anyone of the family members. talk to here friendly and gentle try to make her open to you.
She will be mad at you for searching into her stuff just tell here that she was blocking you everywhere and you were worried about her, the most important thing your need to do here is try know if she is doing any kind of drugs, you know that all or most of teens are seeking for attention no matter what , share your experience with her and give her advices and examples , then give her some time if she didn't not change or not even trying to, then you need to tell your parents so they can deal with her and help her before it's too late

Have a wonderful day (｡◕‿◕｡)