I too would second the suggestion about Dallas Children's Chorus. Has your daughter had any piano yet? She really needs to be able to read music and have some rudimentary music knowledge ( i.e. pitch, rhythm, note values, etc.)before she starts voice lessons. I would be very suspicious of any teacher that would take her without it. A choir, be it church, school or community is the best way to develop these skills. Voice lessons are really for more advanced voices. The voice itself does not even fully mature for girls until they are 16 or 17 years old. I have turned away many younger students for this very reason. Hope this helps!
Take it from someone with two degrees in music...