Jing-mei's feelings change as the story progresses. At first, Jing-mei is as excited or even more excited than her mother is.
In fact, in the beginning I was just as excited as my mother, maybe even more so. . . In all of my imaginings I was filled with a sense that I would soon become perfect: My mother and father would adore me. I would be beyond reproach. I would never feel the need to sulk, or to clamor for anything.
Her initial excitement makes sense. Jing-mei sees the fame of and reverence for Shiley Temple, so it makes sense that Jing-mei also desires that kind of fame and success. Jing-mei admits that being a child prodigy would also end her feelings of inadequacy in her parents' eyes.
However, as the story progresses, the reader sees Jing-mei's attitude completely shift. Jing-mei is fed up with always disappointing her mother.
And after seeing, once again, my mother's disappointed face, something inside me began to die. I hated the tests, the raised hopes and failed expectations. . . I won't let her change me, I promised myself. I won't be what I'm not.
From that point forward, Jing-mei intentionally did poorly on her mother's tests. It was a coping mechanism, because you can't fail at something that you don't try to do well at. Unfortunately, Jing-mei's spiteful attitude ended up destroying the relationship for years to come.