Many harp teachers (or any musical instrument teachers, really) will give an introductory meeting/lesson for goal setting and assessing the match of student and teacher, so you may want to request such a meeting.
Your daughter’s harp teach should be able to read notes, know the right way to sit and how to play with speed and grace. The teacher should be firm(you will learn a great deal more) but not harsh. Be prepared, after a couple years if the teacher does not take lessons themselves, they may run out of things to teach and you will have to find another teacher. MAKE SURE THEY HAVE LOADS OF EXPERIENCE!!
It’s important to know what the teacher’s credentials and training are. Harp is one instrument that is not successfully self taught. A teacher who is self taught can cause damage unintentionally. An understanding of a proper technique is critical to healthy playing. The underlying principal of all good technique is a relaxed approach with a well aligned body. If the teacher has a degree in harp or has taken lessons for a number of years that’s a good sign. Find out who your harp teacher studied with and look them up on the web, see if they have a solid reputation.