If you are not self harming to the point of needing medical attention, then I would be a bit concerned about T threatening to tell your parents. Also, the fact that she can not respect you as an adult (going to seek supervision) is understandable as to why you would lose trust in her.

Did you guys have an agreement that she would tell your parent if she found out? Did she find out or did you tell her? What was her main concern in wishing to contact outer sources? Was it a bad episode?