According to Jing Mei's mother, Jing Mei is not the best child prodigy type girl in the world because Jing Mei doesn't work hard enough at it. The mother does not believe too much in natural talent and ability. She believes that through enough hard work a person can become anyone and do anything.
"Of course, you can be a prodigy, too," my mother told me when I was nine. "You can be best anything.
Mother's first attempt at pushing Jing Mei toward stardom involved sending her to beauty school. Jing Mei's mother believed in the idea of "look smart to be smart." She wanted Jing Mei to look like the Shirley Temple girl in order to be like Shirley Temple.
At first my mother thought I could be a Chinese Shirley Temple. . . Soon after my mother got this idea about Shirley Temple, she took me to the beauty training school in the Mission District and put me in the hands of a student who could barely hold the scissors without shaking.
After attempting to look the part, Jing Mei's mother then put Jing Mei through a battery of tests. She's trying to find Jing Mei's niche and then train her to stardom through it.
About halfway through the story, Jing Mei decides that she has had enough of her mother's pushing. Jing Mei begins to push back and try to do poorly. The method works until Jing Mei's mother sees the girl on TV playing piano. Jing Mei's mother comments that the girl isn't that great and then the following verbal exchange happens between Jing Mei and her mother:
"What are you picking on her for?" I said carelessly. “She’s pretty good. Maybe she's not the best, but she's trying hard." I knew almost immediately that I would be sorry I had said that.
"Just like you," she said. "Not the best. Because you not trying." She gave a little huff as she let go of the sound dial and sat down on the sofa.
It's clear from that quote that Jing Mei's mother absolutely believes that Jing Mei isn't the best, because she simply isn't working hard enough.