If the school gave her permission, couldn't she carry in the classroom?
If she has permission from the right people, yes.
(a) This chapter does not apply to the following:…
(2) A person who may legally possess a firearm and who has been authorized by: (A) a school board (as defined by IC 20-26-9-4); or (B) the body that administers a charter school established under IC 20-24;to carry a firearm in or on school property.
Ind. Code § 35-47-9-1
The board of the school my children attend - consisting solely of me and my wife - has unanimously authorized the possession and carry of firearms on school property...
My children attend in a similar district.