Imir Byrd spent his entire kindergarten year on a laptop. To say he was excited to return to in-person school Tuesday — the first day of classes for 120,000 Philadelphia School District students — was an understatement. His Batman mask in place, the little boy bounced and beamed across the playground at Powel Elementary, eager to start first grade.

“He recognizes his friends from Zoom,” Imir’s mom, Mercedes White, said as she watched her son race around before going into Powel, an elementary school with a brand-new building in West Philadelphia.

With both high hopes and nerves, students and educators in 200-plus schools waded into the unknown: the third COVID-19-touched school year, but the first term starting with masks and a looming vaccine mandate for all staff, set against a backdrop of expiring teachers’ and principals’ contracts, bus driver shortages that changed school start times across the city, and facilities concerns across the district.

Most Philadelphia students have been out of buildings for 18 months.

White, Imir’s mother, was glad her boy was happy. But she’s also wildly nervous — White works for the city’s health department, and watched warily as schools opened, and some closed after COVID-19 outbreaks, in other parts of the country.

“I have some doubts about kids under 12 being in school,” said White. Imir wears a mask without fuss, but she’s anxious about what happens when he has to take it off. Many Philadelphia schools will not be able to maintain social distancing, but instead will rely on masks, hand-washing, and other mitigation measures.

“It’s lunchtime that I’m nervous about,” said White.

Superintendent William R. Hite Jr. has said schools must get creative to keep children three feet apart during breakfast and lunchtimes, using outdoor spaces when possible. He has acknowledged that social distancing will require extra staff, which he said the district would use federal recovery money to pay for.

There’s a lot that Powel principal Kimberly Ellerbee can’t control, but she was focusing on what she could — making sure students were with the right teachers, reassuring shaky parents, setting an upbeat tone.

“You are here today to prepare to change the world!” Ellerbee told her students, shaking a blue-and-yellow pompon and smiling. “You can do this!”

Powel, a K-4 school, shares a new building with Science Leadership Academy Middle School, which educates kids in grades 5-8. The $40 million structure, on the site of the old University City High School, which the district closed in 2013, was built privately and paid for with $7 million in district funds and $33 million in philanthropic money. The land came from Drexel University, which also raised the donated money from outside donors.

“It’s a beautiful place to learn,” said Timothy Boyle, principal of SLAMS, which opened six years ago and has had to move three times.

Of leading a school during COVID-19, Boyle said: “Everything goes a little more slowly and cautiously.”

The school district will soon require all staff members to be vaccinated; officials are in negotiations with the system’s five labor unions to determine a vaccination deadline, exemptions, and consequences for those who do not comply.

“Teachers have rights and the staff have rights,” said Boyle, who said he was vaccinated. “We’re wildly pro-vaccination.”

Hite, Mayor Jim Kenney, and school board president Joyce Wilkerson were on hand at Powel and SLAMS, ringing bells and cheering on students.

“We’re excited to get kids back,” said Hite. “Seeing the young people back — we can return to what people know how to do, to serve children.”

Still, questions remain.

Rosaline Turner was up for most of the night before her son Anthony’s first day of kindergarten at Powel. She knows Anthony, who attended prekindergarten in person last year, is ready for school, and she’s thrilled with his teacher assignment and with the new school building.

What kept her up?

Fears that a COVID-19 outbreak would soon send Anthony or his sister, who attends Middle Years Academy, also in West Philadelphia, back to virtual learning.

“I really don’t know how to keep him focused on a laptop,” said Turner.

Still, she saw her son’s broad smile and thought: It’s a good day.

“Let’s keep all our children in prayer,” said Turner. “Let’s keep moving forward.”

Syrita Powers is trying. But there are still kinks to be ironed out, she said. The West Philadelphia mom has three children in district schools, two at Barry Elementary and one at Heston Elementary.

Logan and Madison’s school bus never showed up. Georgia’s bus did, but the driver didn’t have a record that the little girl, who has multiple disabilities, has a mask exemption for medical reasons.

“It was tough,” Powers said of the start of school for her family.

Powers sent her children with cleaning supplies. She had Logan, who is 13, vaccinated, and taught her to wipe down things like door handles herself. She hopes paraprofessionals will sanitize things for her younger girls, both of whom are nonverbal.

“Because of the delta variant, I’m nervous,” said Powers. “But we’ve done all we can do.”

After the school day had ended, Randolph High School teacher Cheryl McFadden breathed a sigh of relief. The growing career and technical school in Nicetown now has more than 550 students, and at one point McFadden, an English teacher, was expecting one class of more than 50 students.

Her largest turned out to have 36 children.

“That’s not ideal, but it’s manageable,” said McFadden, a veteran teacher. She wanted to put three feet between students per the CDC recommendation, but that’s just not possible. Neither is opening classroom windows — her classroom, like many at Randolph, has none.

Still, she was delighted to welcome kids back. She identified some students she taught last year by voice, and gave hugs to the ones who asked for them.

“My heart melted,” McFadden said. “I fell in love with teaching again.”