Let us return immediately to the Emerald City and prepare to start on our journey early tomorrow morning." Glinda was not quite satisfied with this plan, but could not think of any better way to meet the problem.

She knew that Ozma, with all her gentleness and sweet disposition, was accustomed to abide by any decision she had made and could not easily be turned from her purpose.
Moreover she could see no great danger to the fairy Ruler of Oz in the undertaking, even though the unknown people she was to visit proved obstinate.

But Dorothy was not a fairy; she was a little girl who had come from Kansas to live in the Land of Oz.

Dorothy might encounter dangers that to Ozma would be as nothing but to an "Earth child" would be very serious.
The very fact that Dorothy lived in Oz, and had been made a Princess by her friend Ozma, prevented her from being killed or suffering any great bodily pain as long as she lived in that fairyland.

She could not grow big, either, and would always remain the same little girl who had come to Oz, unless in some way she left that fairyland or was spirited away from it.