I used to always start my students on a soft top(6-8 ft, depending on size).
1. Inexpensive(100 complete at Costco)
2. It will give your daughter more confidence since less dangerous
3. Very floaty and easy to catch waves.
4. Very stable. Also makes it hard to turn, which is not a bad thing when you are first learning.
I also noticed that the younger they started, the easier they picked it up, especially the girls. Maybe better balance and lighter.
Within a a few days, most all the younger ones(under 15) were all standing riding whitewash. And by the end of the 3 week class, all were able to drop in and actually ride left or right. Again, not much turning yet, especially with those boards. Most purchased regular, smaller boards after the class was over. My niece, who is about your daughters age, is in the process of learning on a soft top my brother got her and doing great. One final note, the kids definitely had more fun and gained more confidence when they learned with buddies or a small group with similar ages.