Perhaps you could begin to build a working rapport with this teacher by
telling her you plan to have the students start a portrait unit and she
will be featured as the first subject. This way she will have an interest
in the success of the project. How about inviting invite her into the room
for a formal sitting. Sometimes non-art teachers have no idea of what
takes place in the art environment, and how it can vastly differ from
non-specials subjects. Good luck, Diane L.