I would definitely recommend starting with at least a folk/celtic harp and preferably a lap harp. I play harp at a beginner level and have very small hands. Some of the folk and lap harps have closer string spacing that is easier for those of us with small hands. Also, a large harp could very well have strings that an eight year olds arms are not long enough to reach so it would functionally be a smaller harp for her.
Many if not most pedal harpists start with a folk harp to learn the basics on. Smaller harps are also much easier to transport to lessons, recitals, ect.