The arrest came as Georgia lawmakers were crafting what would become one of the nation's toughest crackdowns on illegal immigrants, and Guerrero feared that her mother would be deported.
"I feel like that was my breaking point, when my mom was in jail," said Guerrero, who came to the U.S. from Mexico when she was 2. "I felt like, well, that's it, it can't get any worse than this. My mother has been to jail."
Guerrero publicly announced her immigration status at a protest in March, and now she is organizing a rally under the tutelage of more experienced activists who are only a few years older.
The high-stakes movement of young illegal immigrants declaring that they're "undocumented and unafraid" got a boost this week when a Pulitzer Prize-winning journalist revealed he has been living in the country illegally.
Guerrero is the organizer of a rally set for Tuesday at the state Capitol for high school-age illegal immigrants to tell their stories. The recent high school graduate and others hope to draw attention to the plight of the hundreds of thousands of young people who were brought to the U.S. illegally by their parents.
Efforts by young activists around the country have ranged from rallies and letter-writing to sit-ins and civil disobedience, with the aim of forcing the federal government to reform rules for immigrants in their situation.
In one of the most high-profile declarations yet, former Washington Post reporter Jose Antonio Vargas used an ABC News interview and a New York Times Magazine article to announce Wednesday that he is an illegal immigrant from the Philippines.
"It's very exciting," said Mohammad Abdollahi, 25, a protester who is helping Guerrero. He said Vargas' revelation "shows that we exist in all walks of life."
Some people in the community fear Vargas' admission that he used false documents to get a driver's license and a job could invite backlash.
Those who come forward make themselves vulnerable, Abdollahi said, but it's no guarantee they'll have to leave the U.S. right away. Some have been deported despite support from their communities asking that they be allowed to stay. Others, like Georgia college student Jessica Colotl, have won at least temporary reprieves.
Mandeep Chahal, an honors student at the University of California Davis, and her mother were granted a stay in their deportation proceedings Tuesday after Chahal, 20, campaigned on Facebook to avoid being sent back to India.
Proponents of stricter enforcement of immigration laws often concede that young people in this situation are among the most sympathetic cases but that legalizing them still raises problems.
"Our own American young adult college grads are in dire straits in the job market -- and particularly disproportionately Hispanic and black Americans -- so what the DREAM Act does is adds potentially a million, 2 million more people to compete legally in that job market," said Roy Beck, the executive director of NumbersUSA, which pushes for tighter immigration control. (The act would provide a path to legalization for certain young people brought to the U.S. illegally by their parents.)
"So, as compelling as the case of these DREAM students is, we have to acknowledge that legalizing them does actually victimize our own young adults," he said.
Guerrero has been working to attract participants for next week's rally by telling friends how relieved she felt after speaking out. She said she never tries to push people to reveal they're in the U.S. illegally unless they understand the consequences.