The Anaxa should be fine. I played the Clarinet and Flute and when I started we rented the instruments and that was good, because the first flute I had gotten was not comfortable because of the key span. I have small hands, so I was able to get into a Bundy which was more comfortable for my hands. That would be my biggest concern.
As far as quality, pads can be replaced and keys adjusted, so yes it can carry her through the 6th-9th grade if she is happy with the way it handles. Joan