When she was younger, Barbara Ferreira never imagined she’d be her school’s valedictorian or the first in her family to attend college. At times, she wasn’t even sure she would get to stay in the United States until graduation.

In middle school, the Brazilian immigrant was an indifferent student. She had other concerns, as her mother struggled to support Barbara and her older sister by cleaning houses, and they worried about their immigration status.

“I was never really confident in school,’’ said Ferreira, 18. “I was always the quiet student in the back of the room who was scared to give an answer, because I always felt like it wasn’t the right answer.’’

But last week, Ferreira stood before her teachers and classmates as valedictorian of City on a Hill Charter Public School, where faculty members said she has been not just a hard-working student, but also a compassionate member of a community.

Guidance counselor Diana Mastrocola said she first noticed Ferreira during a lunch break on a day of MCAS testing.

“She was just so bubbly, and energetic, and encouraging: ‘Come on, guys! We’ve got this! We can do this!’ ’’ Mastrocola said. “And then the second we restarted the testing, she was focused, back to work, serious. She doesn’t rush through things. She really pays attention to detail.’’

Ferreira said she developed close relationships with teachers at the Roxbury charter school, who recognized that she was struggling early on, as she transitioned from a traditional public school as a freshman. Because she lacked confidence in her academic abilities, she was hesitant to ask for help.

By her senior year, it was clear that she was uncommonly intuitive and inquisitive, said Nick Delis, who taught Ferreira in an Advanced Placement government class.

“We were doing notes and just throwing questions out there’’ on the first or second day of class, Delis said, “and it seemed like she, more than any other student . . . really understood how the system worked, how government worked, even before we dug out all the information that they needed.’’

Ferreira’s academic trajectory changed about six years ago, when her mother became the live-in housekeeper for a busy Jamaica Plain husband and wife, both business owners. The couple and their daughter have encouraged Barbara to see her potential and strive for achievement, she said.

“They helped me a lot, telling me how the school system works here in Boston,’’ Ferreira said.

“They hired me a math tutor when they found out I was struggling in math. . . . They said they believed in me, even though I never did very well in middle school.’’

Ferreira’s mother, Cacia Oliveira, said her employers treat them like members of their family, and she is grateful that they have embraced Barbara as if she were their own child.

Mother and daughter have come a great distance in both miles and circumstances.

They immigrated to Massachusetts from Governador Valadares, Brazil, as a family of four — mother, father, and two little girls — when Barbara was 2.

They settled first in Westborough, then lived in several Central Massachusetts communities.

“We came here . . . for the American dream,’’ Ferreira said. “We just felt like there’s more opportunity here.’’

That dream took a hit when her parents separated. Barbara was 5 and her sister Rafaela was 11, and the girls and Cacia were all in the country as the father’s dependents. During the acrimonious split, he attempted to legally disavow them and have them sent back to Brazil, Ferreira said.

If they had been deported, she said, they would have returned to Brazil with nothing. But the judge was compassionate.

He allowed the two girls and their mother to stay in Massachusetts legally and to appear in court separately from the girls’ father.

That didn’t mean their immigration status was sorted quickly or easily.

“We’ve actually been in the same process [since] 2001,’’ Ferreira said.

“My judge retired recently. That’s how long it’s been, and I still haven’t received my green card.’’

Her immigration status nearly derailed her academic ambitions. Because she is not yet a US citizen or lawful permanent resident, she isn’t eligible for most financial aid. She worries that some of the 15 colleges she applied to may not have considered her because of her status.

Mastrocola, the guidance counselor, said dealing with her immigration status has added anxiety to a time in Ferreira’s life that would have been tense anyway.

“It was really, really stressful, just going through this process and having more doors closed on her than opened,’’ she said.

In the end, Northeastern University accepted Ferreira and gave her a full scholarship. She plans to major in entrepreneurship and innovation — so she can follow Cacia’s employers into the business world — and maybe minor in Mandarin, so she is prepared for the global marketplace.

Already, Ferreira’s success is beyond anything Cacia could have imagined.

“I’m very proud. I see that she has a vision that we don’t really have in our small family,’’ she said in Portuguese, as her daughter translated. “I believe in her; I believe that she can conquer all.’’

Jeremy C. Fox can be reached at jeremy.fox@globe.com. Follow him on Twitter @jeremycfox.