Love the way you talk, Sail
Sail's right. Not everything is your fault. Don't blame this whole ordeal on yourself. If she goes to juvy, well, it was her choice to take that risk. But if you feel like she was hurt by you not paying much attention to her, try apologizing anyway, if only just to relieve some of her stress she's dealing with. Let her know you're there for her no matter what and that you truly care about her as a friend, and if she makes any indications she might commit, tell someone immediately. You aren't betraying her trust; you're protecting her. After that, whatever decision is made about juvy will happen. Don't take any more blame for it.
God bless you both!
Just because everything's changing
Doesn't mean it's never been this way before
All you can do is try to know who your friends are...