Middle age is coming for millennials, including Lena Dunham, who celebrated her fortieth birthday today. The writer, director, and actress became a polarizing representative of her generation even before her character on “Girls” declared, in the show’s première, “I think that I may be the voice of my generation—or at least a voice of a generation.” Lovers and haters have debated her œuvre and public persona ever since, and Dunham remains a figure of cultural fascination: pandemic-era rewatching of “Girls” won the HBO series new fans and led many former critics to declare that it had been underappreciated; Dunham’s latest memoir, “Famesick” (her second), immediately hit No. 1 on the Times best-seller list.

Dunham made her New Yorker début in 2012, during “Girls” ’s breakout inaugural season. She returned that summer with “First Love,” an essay that touched on the quintessentially millennial subjects of awkward sexual encounters, “Dawson’s Creek,” and making a fool of yourself online. Getting blocked on Facebook by her ex’s mother inspires a walk down memory lane, albeit a short one, given that Dunham had only recently turned twenty-six. The version of herself that Dunham presents is simultaneously self-aware and oblivious, silly and perceptive—evoking, in other words, most of us when we were young. The unexpected object of her affection was a fellow Oberlin student, clad in “hemp cargo pants” and large mittens. Dunham describes the innocence and confusion of the sixteen months that followed, but doesn’t claim to have learned much. “Relationships often change people, but this was a weird one,” she writes, “because I was the same before and after.”