Sister, all you can do is carry on being a good friend to her and advise her, End of the day its up to her wheter she wants to wear the scarf, some girls think it restricts their freedom,

She probally wants to have a boyfriend and that, but what can you do, its her life,
if you think her behaviour wil affect your imaan , then i suggest you withdraw from her slightly,


I hope inshallah she see,s the right way, and she is lucky to have a friend like you,