I think speaking with the teacher is a great idea, however, I would also see if there was a way to observe your daughter in the classroom without her knowing you were there. When my daughter was in preschool parents could observe through a one-way mirror class interaction, as well as arrange to join the class. This allowed us to observe what was happening without the teacher(s) and/or students adjusting their behaviors for guests.
Even if the teacher is supportive, it's important to get a feel for social aspect of her classroom. What I mean is that a supportive teacher isn't enough if your daughter is receiving the message from her peers that she is "different and different is bad", on a regular basis. This could be a direct result of teasing, etc. or just based on your daughter's own observations. And ask yourself, if you are confident that regardless of the reason the teacher, school administrators, etc. can find a solution that will help your daughter. If not, then I'd go back and review your other options.
