She remembered key events in “the Troubles,” as the conflict was called, “like they were yesterday,” she said: the 1994 cease-fire, Mr. Clinton’s visit and the 1998 Omagh bombing. “But a lot of it for me was just having to go a different way to school because of a bomb scare,” she said.

“Derry Girls” debuted on Channel 4 in Britain in January 2018 and was an instant hit: It became the most watched television show in Northern Ireland since records began in 2002, with a 64 percent audience share. On Netflix, it attracted a global audience, including from India, Pakistan, Mexico and the United States .

In April 2018, Gleann Doherty, a tour operator in Derry, added a “Derry Girls” guided walk to his repertoire. A 90-minute tour around the show’s locations, it was particularly popular with fans from the United States, Canada and New Zealand, he said in a telephone interview, adding that many international viewers said they watched the show with subtitles to decode the accent and slang.

“It’s now my second most popular tour, after the Bogside tour,” Doherty said. “Now for every ticket I sell for the City Walls tour, I sell five for ‘Derry Girls.’”

The show has been commissioned by Channel 4 for a third series, which McGee is writing now. In time, she said, she would like to take the story up to the Good Friday Agreement that ended the conflict in 1998.

What makes “Derry Girls” unique is the light touch it uses to deal with the heavy hand of history. “We couldn’t present that dreary Northern Ireland again, where it’s always men in leather jackets, everything’s gray and nobody has a sense of humor,” McGee said.