Tell her. She probably already knows, and she probably wont be surprised. But she will be happy you told her instead of someone else or her dragging it out. I didn't tell my T about my cutting at first, which made it difficult later because i wanted to tell but didnt know how. but my mom ended up telling her a few months in. Of course this made me defensive and angry so i denied it and then refused to talk. She almost called the cops and sent me to the hospital for that one. My T told me Take control of the situation and be the one to her. That way you arent caught off guard and become defensive good luck!!