No, it's not unreasonable to expect a response within a day or two. Maybe the teacher doesn't know how to respond, or maybe she's intimidated in some way because you've done advanced work with her. I've gotten that response from my kids' teachers, although it was not intentional. I think knowing that I teach advanced high school math puts them on the defensive.
I would recommend a face-to-face meeting at this point. If the teacher already feels defensive, emails will only exacerbate those feelings.
