I would call the therapist and see what they think. I am in my forties now, my parents never took me. I will say as an adult it’s much more infrequent, when I tell people I am a stutterer they say they never noticed. Sometimes just stopping and taking a deep breath and relaxing your body can help her get something out. Sometimes it seems like your mouth can’t keep up with your brain or something along those lines. You’re an awesome Mom for seeking help for her I stead of ignoring it! Just make sure she knows we all have struggles and she is still just as worthy as her peers that do not. I had so much internal shame as a child.