Maria Mendoza-Sanchez, a Highland Hospital nurse in Oakland, and her husband this week ended their fight to remain in the U.S. after federal immigration authorities denied a last-ditch plea to stay.

Maria, her husband Eusebio Sanchez, and their 12-year-old son, Jesus, boarded a flight at San Francisco International Airport for Mexico City less than an hour before a federal deportation order expired late Wednesday for the couple -- leaving behind their three daughters, two of them adults and one a teenager.

Sanchez spent her last day in the U.S. doing somewhat routine things: She took her daughter, Elizabeth, 16, to her first day of school as a sophomore and she went to the bank.

But she did some out-of-the-ordinary things, too: She granted power of attorney to her eldest daughter, Vianney, 23. She packed her belongings. And she put her nursing uniforms into a storage box.

“I’m sorry I won’t be there to serve them anymore,” she said of her patients in the oncology and cardiology unit of Highland Hospital, Alameda County’s trauma center. “But one day I will be back, that’s for sure.”

The couple came to the U.S. more than 20 years ago, settling in Oakland in 1994. Maria graduated from Holy Names University with a nursing degree while raising their children. Eusebio worked in construction and eventually became a truck driver.

The couple have no criminal records, and have been undocumented during their time in the U.S. Vianney is protected under Deferred Action for Childhood Arrivals, while their three younger kids are U.S. citizens.

“Fighting an immigration case when you are a Mexican is really three times as difficult as it is other communities,” Maria said as she tried to hold back tears. “It doesn’t matter how hard you work. It doesn’t matter what you do.”

Under the Obama administration, the couple received two stays, along with legal work visas, to remain in the U.S. But when they applied for another stay in May 2017, federal immigration officials limited it to 90 days -- after which they would be deported.

The family was hoping for a reprieve with the help of Sen. Dianne Feinstein. But on Tuesday afternoon, Feinstein called to tell them that federal immigration agents had denied their request for another stay, the senator's office said.

"All possible avenues to delay their departure have been denied by the Trump administration in what I believe is an act utterly devoid of humanity," Feinstein said in a statement. “This is a travesty, plain and simple, and evidence that Donald Trump’s immigration ‎policy is nothing more than a hateful deportation program targeting law-abiding families. It’s shameful and stands against the very ideals upon which this country was founded."

In a statement to KQED from  Immigration and Customs Enforcement, Western Region, the agency confirmed the denial. But ICE added that it gave the couple enough time “to get their personal affairs in order and make preparations for their departure.”

Sanchez said she and her husband prepared their three daughters for life without them in the U.S.: Vianney, a graduate of UC Santa Cruz, will be the legal guardian of Elizabeth as she finishes high school. Their middle daughter, Melin, 21, will stay to finish her last year at UC Santa Cruz.

In Maria's last hours before flying to Mexico City, Elizabeth came home from her first day of school. She sat on the couch next to her mom and rested her head on her mom’s shoulder.

The two discussed her first day of school — knowing moments like these were coming to an end.

Maria said she also had a conversation with her kids that a parent doesn't ever think they'll have.

“Yes, indeed, you separate from your parents but you don’t have to worry about rent, you don’t have to worry about food, and then you’ll be able to finish school,” she recalled telling her daughters.

Though she is having to leave, Sanchez said what she's taking with her to Mexico -- her memories -- no one can take away.

"Because it’s in my heart and it’s in my mind," she said.