The third and final "first" day of school in New York City commenced on Thursday morning with lines of sleepy students waiting to enter middle and high school buildings, tapping on phones with masks on and earbuds in.

The last stage of the school system’s staggered plan reopened middle and high school buildings to kids for in-person learning, completing Mayor Bill de Blasio’s ambitious plan to bring students back to the city’s 1,600 public schools.

"We did it. You did it. New York City did it. This is an absolutely amazing moment, fighting back this pandemic," de Blasio said at his Thursday press briefing. "We did something that other cities around this country could only dream of because we have fought back this pandemic so well for so long, because we had the will and the focus to bring back our public schools for the good of our kids, our families, and all of New York City. This is a key moment in our rebirth. And a lot of people said it couldn't be done and it was tough, but we did it and we did it together."

The city’s schools will now have 521,000 students coming for in-person learning, while another 480,000 students have elected to enroll in remote-only learning.

At Brooklyn Tech High School in Fort Greene, school staffers guided students to stand on yellow dots painted six feet apart on the sidewalk, repeatedly yelled offers of free breakfast to the waiting kids, and reminded them to have their health screening forms ready for check-in.

Senior Zaantul Iqbal, 16, said the school year’s strange journey couldn’t end soon enough for her, if only because she has so much work already since remote learning started September 21st. "I'm about to catch senioritis for the fact that they're loading us up with so much homework already,” said Iqbal, who skateboarded to school from her downtown Brooklyn home.

On the sidewalk outside Highbridge Green Middle School in the Bronx, principal Kyle Brillante greeted each student and gently reminded them to pull their masks over their noses and fill out their health screening forms.

“I’m excited. It’s been seven months waiting for this day,” Brillante said. “Seeing the kids with their friends, their classmates, seeing the kids with their teachers. Everything’s been building to this and I'm excited it's finally here.”

Staffing issues remain the biggest obstacle in what was already a convoluted plan to reopen the country’s largest school district, and the teacher’s and principal’s unions have both called for the city to hire thousands more teachers to handle the increased number of in-person and remote classes. The unions have also repeatedly clashed with de Blasio and Chancellor Richard Carranza over demands for improved ventilation in school buildings, increased supplies of personal protective equipment, and random testing of teachers and students.

In a reminder that the COVID-19 rates in the city were starting to increase, de Blasio also announced Tuesday that one Elmhurst special education school is closing for 14 days and its students shifting to remote learning after two cases were reported there, following Department of Education protocols. Meanwhile, the United Federation of Teachers union president Michael Mulgrew also warned that the union would press to close schools in specific neighborhoods with increasing COVID-19 rates instead of waiting for a city-wide shutdown -- "if that means we have to go to court or do something else, we will,” Mulgrew said at a press conference Thursday.

Even on the first day of school, Brillante said he was still juggling the medical accommodations of his teachers and shifting staffing around at the last minute.

He judged morale as “cautiously optimistic or neutral” among his teachers, Brillante said. The day before, he polled his teachers: “how many of you are anxious? How many of you are neutral? Most of them said that they were cautiously optimistic or neutral. We only had one who said she was a black hole of despair.”

Students queue up outside of Brooklyn Tech High School on the first day of in-person learning.

Students queue up outside of Brooklyn Tech High School on the first day of in-person learning.

Students queue up outside of Brooklyn Tech High School on the first day of in-person learning.

Students said they felt the day was proceeding smoothly at Brooklyn Tech, one of the country’s largest high schools, with more than 6,000 students in total. On a normal school day, “there's like this flood of people,” said sophomore Alexander Honeyman, 15, of Long Island City. “It feels like thousands of kids funneling in through like three or four doors.”

There were about 700 students expected for in-person learning Thursday, said one staffer who declined to give his name but was hailed as “Coach” by several students waiting in line. "We're a large school, and that's why there's a sense of feeling safe," he said. "The kids will be spaced out, have a school that is as big as this school, you know, no one is on top of each other."

Honeyman said the school’s size was an advantage: “I think the school is big enough to accommodate all of it safely,” he said of the nine-story school.

Being back in the classroom was a welcome break from remote learning, many kids said.

Joel Im, 15, a Brooklyn Tech sophomore from Sheepshead Bay, said it was difficult to concentrate on schoolwork at home with his younger brother clowning around on his laptop: “I find it easier to be in a classroom and learn rather than set up at my own desk where there's lots of tiny distractions like my younger sibling,” Im said. “I have one younger brother, and he does not know how to work the computer.”

Iqbal said that while she is a “visual learner” and appreciated some of the display-heavy aspects of online learning, she was looking forward to engaging in a classroom setting as well.

“There's certain classes that I need a person-to-person connection with. Like I struggle with math, so I would need a teacher there,” she said. “So I guess hybrid learning is perfect.”