On the first day of classes Monday, Fairfax County Public Schools science teacher Shawn Stickler barely made it three names into his attendance list before he stopped and gave a double-take.

Stickler, who leads seniors in an oceanography research class at Thomas Jefferson High School for Science and Technology, peered up in mock disbelief at a tall, gangly high school senior in a black mask.

“David?” he said. “This is the first time I’ve seen you not in your bed. You’re actually tall — wow.”

The boy blushed and laughed behind his mask. His classmates joined in, chuckling.

A year and a half into the coronavirus pandemic, everyone in the room could relate to the strangeness of finally meeting someone in person who for a long time had existed only as a rectangle on Zoom.

Across the Fairfax district Monday, students, parents, teachers and staffers took similar first steps — a little awkward, a little hopeful — into a school year that administrators across the state have promised will consist of five days a week of face-to-face instruction, after two school years in which the coronavirus upended education.

Fairfax was not the only D.C.-area school system to open Monday. Schools in Virginia’s Manassas Park, Prince William County and Culpeper County also launched their fall semesters. Alexandria City and Loudoun County public schools are slated to open their doors later this week, with more D.C.-area systems following throughout August and into early September.

Fairfax, whose 180,000 students make it the largest district in Virginia, is returning more than 99 percent of its student body to bricks-and-mortar classrooms, according to spokeswoman Julie Moult. After more than 18 months of online learning for many, Fairfax allowed only students who could prove a medical need to attend class virtually this year — a group that ultimately included about 400 children, Moult said.

Fairfax Schools Superintendent Scott Brabrand, who said he spent Monday morning visiting classrooms, said he was pleased with the high rate of in-person enrollment. He said he was also happy that he has faced little blowback over his school system’s decision to require masks for everyone, regardless of vaccination status, and to mandate vaccinations or regular testing for staffers.

“My biggest hope for this school year is that people in a few months will be saying, ‘What pandemic?’ ” Brabrand said. “The delta variant has lengthened the tunnel, but there is light at the end of this tunnel — and the restart of school in person is another marker of putting the pandemic in the rearview mirror.”

For some Northern Virginia students, Monday represented their first time inside a school building in more than a year and a half. For others, it was their first time ever inside a school.

There were small stumbles. Students across Fairfax’s dozens of campuses struggled to find their classrooms, wandering the hallways after the bell until they were helped on their way by a staffer with a clipboard. Neighborhoods — including some shocked-looking joggers — had to readjust to the morning crush of cars as parents dropped off their children in long-unused kiss-and-ride loops.

And in Niketa Knight’s fourth-grade class at Stratford Landing Elementary School, none of the dozen masked students quite knew what to do with their hands — or where to look — when she asked them to gather in a circle on a colorful, rectangular rug.

Still, the girls and boys complied, shuffling forward, eyeing one another and fidgeting with the ear loops to their masks. One boy, clad in slacks, a button-down long-sleeve and a bow tie, grimaced and tugged at the heel of his leather dress shoes, which pinched.

“So, boys and girls,” Knight asked, “how many of you remember a game from two years ago called ‘Just Like Me’?”

Most of the class looked puzzled. One boy piped up to explain: The last time he played that game, he said, he was in the first grade.

Knight told her students not to worry. She walked the class through the rules of the game, and pretty soon students were taking turns stepping in the center of the circle and sharing something they liked. If their peers agreed, they yelled out “Just like me!” and stepped toward the center of the circle, too.

One fourth-grader said she liked guinea pigs. Another girl said she liked cats. Another liked gymnastics.

Then someone said “I like school” — and the whole group rushed at once to the center of the rug, raising their hands and screaming: “Just like me! Just like me! Just like me!”

As Knight’s students reacquainted themselves with the icebreaker, other long-delayed reunions were taking place throughout the county.

At nearby Glasgow Middle School, Christian Rios and Kusavadee Lyon welcomed their seventh-grade U.S. history class by pointing to a large transparent jug of hand sanitizer and offering spritzes.

As Rios embarked on an opening monologue — announcing he had become an uncle over the summer — a girl with long blond hair spotted a curly-haired girl across the room wearing a mask printed with ladybugs. The blond girl jolted upright in her chair and began waving one hand in a frantic, mute hello.

Her friend in the ladybug mask glanced toward Rios, saw that he wasn’t looking, and then began waving back just as fast.

Elsewhere on the first day of school, though, it was all about saying goodbye.

Back at Stratford Landing, Regan and Jen Cavaliere guided their 7-year-old son to his first-grade class. Stratford Landing allows parents to walk their children to class on the first day.

The teacher bent down so she was at eye level with the boy, before telling him to do three things: First, go find his desk, which he would know was his because his name was stuck on the back of the chair. Then he should hang up his backpack. Only after that, the teacher said, could the boy play with a jar of Play-Doh she had placed on his desk.

The young boy nodded, and the Cavalieres watched as he disappeared inside the room. Regan stood on tiptoe in red sneakers, straining to keep an eye on her son, as other students and parents began filing by the door, obscuring her view.

In addition to suffering the normal jitters that come with parting with a child for the first time, she worried about sending her son to in-person school as the coronavirus continues to surge. She was especially worried about lunchtime, when children would have to remove their masks to eat.

The rise of the delta variant scares her. And, given that their son is under 12, he was starting the year unvaccinated, with no guarantee of when a coronavirus vaccine might be available.

If virtual schooling were an option, Regan said, she would have taken it.

“He’s not crying,” Regan observed to Jen, still peering into the room on tiptoe. It was close to 9 a.m. Most of the other parents had left already, and class was getting underway.

Jen gripped Regan in a bear hug.

“Come on,” she whispered. “You can do this.”

Together — with regular ­glances backward — the Cavalieres walked away down the hallway.