Wow, I am excited for you! I completed the Camino Francis from SJPDP in June of this year with my 23 year old daughter. I have to say that it was a challenge for me the first few weeks because she was a bit (a lot actually) negative about the long distances, being tired, the heat, etc., etc. I started regretted asking her to go, but I saw a change in her after we passed the halfway point.
By the time we got to Santiago her whole attitude had changed. She got up early and her steps were light and joyful, instead of dragging. The day we got our Compostela we happened to walk by the cathedral and a tour guide with a huge group of tourists saw it in her hand and he stopped her and asked her some questions about her trek while on his microphone with the tourists. I have a picture of her glowing and beaming while she proudly answered his questions. I realized then that my trek on the Camino with her will be an experience that she, and me too of course, will treasure the rest of her life. How many parents get to have such a wonderful experience? Some, but not many.
I just went back and completed the Camino Via de la Plata from Sevilla to Santiago this November, and while planning it my daughter asked if she could go. Unfortunately, she couldn't because of work. But, she wants to trek another Camino in May, 2017, with me again.
So, no matter what section of the Camino you decide to trek with her, it will be a wonderful experience for both of you, you will love it! I am excited for you! Buen Camino!