Well, you can't be too kind in a first letter (nothing has gone wrong yet, after all), but it is a bit vague.
I would slip in some casual mention of what DD is interested in, in the interest of acquainting the new teacher with your child.
"DD would love to share her favorite Dickinson poem with the class if you can help her find an appropriate time for it. She gets frustrated with writing sometimes, because her expression hasn't caught up with her ambition yet -- for instance, she struggled with a story about (her favorite characters) from A Midsummer Night's Dream and hasn't finished it yet; perhaps you will have some advice that will help her. She's very happy to work on new things in math, and we look forward to hearing from you about what comes next for her and how we can help to keep her excited and moving forward."
