Friends daughters self harmed.

Today I was looking after my friends daughter she is 14 I was wearing shorts and she noticed my self harmed scares and asked me about them. I didn't really know how much she knew about this so I just said they were old scares from my childhood. The next thing I noticed she was crying I asked her what was wrong and she opened up after a while and said she had the same scares and that some of them are new cuts she showed me them and I realised they needed to be stitched and dressed. My mom is a nurse so I rang her to ask what I should do she told me to take her in to her clinic so I did. On the way I was talking to the little girl about why she thinks she does it and if she had told her mom she told me she hadn't and doesn't want to because she doesn't want her mom to worry. We got my mom's clinic and mom went through with her about everything and asked if she wanted her mom to be called. She said no. So we changed the topic to counseling and sorting out some other methods on coping with what she is going through. On our way home I told her about my story and about why I self harmed and how I found other ways to deal with my problems. And tried to encourage her to let me tell her mom. I'm just wanting some advice on if I should let her mom know that she is struggling or if I should let

Her do it in her own time. I have the wee girl here with me for another couple of days so keeping a close eye on her. Any advice welcome. I know if my son was going through some difficulties I would like to know. My mom gave me some tips on how she handled my period of selfharm. ( also I didn't use the name of the girl for safety reasons) thank you