The mouse may also symbolize vigilance or alertness. In the vignette, we are not really told whether the mice exist or are merely the figments of Alicia's imagination.
What we do know is that Alicia works hard because she does not want to spend her whole life in a factory or behind a rolling pin. There is a sense of immediacy in the prose through the use of polysyndeton. Polysyndeton is the use of multiple conjunctions in close succession in a sentence. We can see this in the story:
Alicia, who inherited her mama's rolling pin and sleepiness, is young and smart and studies for the first time at the university.
In the above quote, the "rolling pin" represents domesticity and traditional femininity. Alicia is afraid that these will subtract from her happiness in life. So, as a mouse must be alert against threats to its existence, Alicia stays alert to the threat of poverty and what she considers unvarying tedium in her life. In the above quote, we learn that Alicia is young and smart. She is also ambitious, being the first in her family to study at the local university.
The mice also represent the threat of poverty, of course. Alicia believes that education will be her ticket out of poverty. She watches and bides her time. Concurrently, she studies and makes an effort to better herself. She takes two trains and a bus to school every day. Alicia's determination to stay "alive," so to speak, mirrors the determination of mice that must remain vigilant in a human world.