Editor's note: This version corrects the number of Groton Public School students returning to school Thursday.

Groton — Vivica Morava, 9, said she was a little nervous starting school this year because she was assigned to her first “guy teacher.”

Two of her fourth-grade classmates didn’t know quite what to make of Mr. Serven, either. Karina Vazquez, 8, thought he’d be tough on them. Anna Jones, 9, said he kind of reminded her of her grandfather, even though he’s not that old.

Matthew Serven is 30 years old and teaches at Mary Morrisson Elementary School. And no, he said, he’s not mean. The girls knew that before lunchtime.

“He’s fun,” they agreed.

About 4,100 Groton Public Schools students went back to school Thursday, the first day for students in grades 1 through 12. Another 400 children are expected to start school on Tuesday, the first day for kindergarten and pre-kindergarten students.

Parents were still registering children this week, while others were disenrolling students, primarily because of the movement of Navy families, Superintendent Michael Graner said.

“We are monitoring it, but we think that we’re in good shape with the staff that we have,” he said.

The school district hired 22 teachers over the summer and had two open positions still to fill as of Aug. 25, said Laurie LePine, director of human resources for Groton schools. She told the Board of Education earlier this week that the district would probably fill the open jobs, an elementary physical education teacher and a middle school science teacher, with substitutes for opening day, but was interviewing candidates.

Assistant Superintendent Susan Austin told the board that class sizes in some primary grades were nearing 22 and 23 students. The increased enrollment affected all elementary schools, but in different grades, she said.

Graner told the board he was considering assigning part-time paraprofessionals to help but would also add teachers if necessary.

He visited six of Groton’s 10 public schools on Thursday and plans to visit the other four today.

Shaun Farquhar, a fourth-grade teacher at Charles Barnum Elementary School, said the children returned to her classroom excited and also greeted two new classmates.

“They were all happy,” she said.

Amanda Daniels, who has three daughters, said her oldest two — ages 6 and 8 — woke at 6 a.m., instantly found their school outfits and “couldn’t wait to say goodbye.”

Daniels brought her youngest daughter, 3, into the school with other parents having their children screened for pre-kindergarten and kindergarten.

“I’m going to miss them like crazy,” she said. “The house is already too quiet with just one.”

d.straszheim@theday.com

@DStraszheim