Lena Dunham can't stop moving.

Sitting cross-legged on a stool in a Los Angeles photo studio, the creator and star of Girls bobs her bare foot energetically — up and down, up and down — as she waits for a camera crew to finish setting up. A long day of primping and posing is coming to an end, but her verve doesn’t fade with it. She looks happy, smiling as she sips a green juice that is pretty much the antithesis of what her alter ego, Hannah Horvath, would consider an ideal snack. (Cupcakes in the bathtub? Now we're talking.)

Of course, the underachieving Horvath has never been a mere stand-in for Dunham, who has been nominated for three Emmys and won a Golden Globe for the series she created when she was just 23. But watching her drink an impossibly healthy, grown-up beverage, it’s hard not to think about how this May, Dunham will turn 30.

That's right: The woman who has given voice to the existential malaise of female twentysomethings is kissing that pivotal decade goodbye.

It makes sense, then, that she's also bidding adieu to Girls, which will end after its sixth season, set to air in 2017. (Season 5 begins February 21 on HBO.) “When I started working on Girls, I was single, I lived with my parents, I was figuring out my career,” Dunham says after the photo shoot, curled up on a couch in the corner of the studio, her face scrubbed clean of makeup and her energy still buzzing. (She tugs at her earlobe almost constantly throughout our chat.) “I feel ready to turn my heart and soul and insides over to something else. It felt right to be turning 30 and moving into this decade with a clean slate.”

One that she's already begun to fill. Last summer, Dunham and her bestie/producing partner Jenni Konner launched Lenny Letter, an online editorial venture that explores contemporary womanhood. When she's not stumping for Hillary Clinton, she executive produced a series pilot for HBO called Max, about a woman (played by Zoe Kazan) striving to make her name in the 1960s magazine world. And these days, Dunham splits her time between Brooklyn and L.A., living the bicoastal life with her boyfriend, musician Jack Antonoff, and their rescue dog, Lamby. Oh, and she's also reading books on fertility