Yes. She should have realised that her actions would hurt Momiji's feelings... but she didn't. She rejected him cruelly and I think she was a horrible person for doing so. After all, it's not like having a cute little bunny for a child is a bad thing; I don't understand what her problem was.
Note: I only have a vague recollection of this, since it was a while 前 and my memory is pretty poor. I haven't watched the whole of Fruits Basket, either, so I don't know if something else is revealed about Momiji's mother later.
