I know that some of her brain cells must've died by that point because of all the choking, but she was also supposed to be a very smart girl. She finds something in her locker and her first suspect (of putting that in there) is her mom? She thinks her mom went to her school in the middle of the day just to do that (and somehow didn't see her)? Or that she broke in at night?
shareHer mother was apparently volunteering at the school a lot and at one point a teacher asked her if she would join her and her mom for lunch. So I can see where she would think it could be her mom.
Where it strayed off for me was the fact that Ryder somehow got into her locker. I know they were good friends, but did he have her combination? This is where her brain should have been sending her alert signals.
"but she was also supposed to be a very smart girl."
She was pretty dumb...Any kid that would intentionally choke themselves for a "high" is a dumbass.