First off, I applaud you for addressing this sooner, rather than later. I wish my parents had gotten me into speech therapy early. I'm a father of three and a (recovered) stutterer. One of my kids has a physical disability. I've always approached doctors, therapy, surgeries, etc directly with him. Tell her the truth. "I love you and I want the best for you. I'm concerned about your stutter. So I looked into it, and I found someone who knows a lot about stuttering. We're going to meet them, and find out more about it." Answer any questions she has as honestly as you can.