Dozen of yellow buses roared into Acton-Boxborough Regional High School shortly after sunrise Monday, as one of a handful of suburban Boston districts welcomed students back in-person.

That is not to say that everything in Acton-Boxborough is back to normal kicking off this school year. Students quietly filed off buses wearing masks. A couple even wore black gloves as an extra precaution.

“I’m a little bit nervous about how it’s going to work out,” said Drew Cudmore, a senior who says the hallways are typically pretty crowded and space is tight. This year, lockers are off-limits and hallway traffic must follow a series of blue-tape arrows on the floor. The new alternating hybrid school day includes one-way stairwells and a process for sanitizing tables after lunch.

It was a first day of school that's already a memorable one. Apprehension about what’s to come hung in the air as students filed inside together, spaced well apart. Only a day earlier, Lincoln-Sudbury, a neighboring high school, announced it would cancel classes in person and switch to remote learning for two weeks after a police broke up a large student party over the weekend.

Acton-Boxborough district officials tried to make the first day of school feel warm and welcoming, if not normal. Staff greeted students as they stepped off buses haltingly, giving other students a wide berth. There were no squeals or hugs, just excitement to be back mixed with a dose of nervousness.

“It definitely feels different from other opening days in the past, it’s definitely much more controlled,” said Superintendent Peter Light, who was visiting schools across the district. “I think everybody is waiting to see what the first day brings.”

Just up the street, dozens of parents walked their lower school students into the McCarthy-Towne Elementary School and the Merriam Elementary School, which are housed in the same facility.

Sarah and Scott Kiernan said a teary goodbye to their kindergartener Annasophia, who was greeted by teachers holding puppets. Leaving a child for their first day of kindergarten is always a big moment in a family’s life, but COVID-19 concerns add a new dimension of emotion.

“We’re worried but excited. You question [yourself]: Am I making the right decision?” Sarah Kiernan said as she watched her daughter enter school for the first time. “That’s the hard part.”