This is kind of a sticky sitiuation, I believe in the motto"my body my choice" but with a teenager different rules apply.
First hand the parent are her parent till she deemed an adult by law and then she can make her own desicions, the parents can actually fight this in a court of law as they are her guardians and unless she can deem her self an adult the parents can make their say.
Life sucks but the law goes both ways here and you need to understand the parents choice as well even if it is wrong morally, im hoping it doesnt go to court but like everyone else said she needs to talk to a counsellor.
Preferabbly she needs to talk to a social worker for childrens aid, they can pull her out and help become an adult as well provide what she needs as was written by both canadian and state laws.