Turning nineteen isn't typically celebrated like the big milestones of turning eighteen or twenty-one. You're technically still a teenager, but the feeling fades away. The impending arrival of your twenties is intimidating, as if a chapter of your youth is about to close. It's a transitional age, an in-between phase, and Leonardo, the nineteen-year-old protagonist of Italian writer-director Giovanni Tortorici ‘s exceptional debut feature “ Diciannove ,” is experiencing this feeling of limbo, this angst of being neither here nor there.

As Leonardo stumbles through his first year of college, chasing some clear idea of who he’s supposed to be, the secure floor of childhood falls away beneath him, while adulthood hovers tauntingly out of reach. Tortorici evidently remembers that disorienting sense of being released (or perhaps abandoned) into the world before you’ve quite found yourself; if you don’t, his funny, nervy, aptly unformed film will give you quivery flashbacks. It’s an auspicious arrival for both the filmmaker and his intense, mercurial young star Manfredi Marini, who holds the camera with the guilelessness of a newcomer and the ease of a natural.

Produced by Luca Guadagnino, for whom Tortorici previously worked as an assistant director, “Diciannove” (Italian for “nineteen,” and apparently being kept as the international title) seems like familiar territory on paper: another coming-of-age story centered on a spirited but charming teen with undefined desires, big dreams, and much to learn about himself. What sets it apart and makes it exceptionally authentic within that genre is its avoidance of the predictable, heartwarming growth arc that typically provides the backbone for such narratives. “Diciannove” follows the tumultuous path of Leonardo's erratic emotions and impulses, offering no tidy life lessons or self-discoveries — only the uneven pieces of knowledge and sometimes harsh realities of life that eventually shape a person.

The film introduces us to Leonardo at a pivotal moment in his life: packing his bags to leave his family home in Palermo for London, where he's scheduled to begin a business degree, as his mother (Maria Pia Ferlazzo) worries with the anxious air of a soon-to-be empty nester. It's a significant step into the world for someone who has spent their entire life on an island, and Leonardo — who's bright, curious, well-read, and, as we'll soon learn, coming to terms with his emerging queerness — clearly wants to be part of something bigger. But he's apprehensive about the trip, plagued by severe nosebleeds that seem to reflect his bottled-up anxieties.

Upon arriving in London, he's greeted by his older sister Arianna (Vittoria Planeta, wonderful) as one escapee might cautiously welcome another. (Credit to DP Massimiliano Kuveiller for capturing the stark contrast in light between the bright Sicilian sun and the dreary British summer, although for Arianna, it's a gray, liberating haze.) Taking a room in her shabby but centrally located Hoxton flat, he's initially caught up in Arianna's big-city lifestyle of clubbing, heavy drinking, and casual encounters, but the allure soon fades, revealing his naiveté: He can't handle his alcohol, and his housekeeping skills are a veritable health hazard.

More importantly, he finally admits to himself that he has no interest in studying business, while he's too far from home to pursue his true passion: Italian literature. With a single, elegant cut — Marco Costa's agile editing aligns with the pace and chaos of youthful whims — he's on a train to the Tuscan university town of Siena, where he's enrolled in a literary degree program. It's a victory for personal freedom, but that doesn't mean Leonardo's life will simply fall into place from here on out. He's still insecure and socially awkward, and before long, he's managed to alienate his roommates, reject a potential friend group, and annoy his professors, whose interpretations of texts he considers stale and misguided. In some ways, he's right; in others, he's not as brilliant a thinker as he'd like to believe.

But hey, at 19, how many people are? Marini, with his quiet confidence, portrays Leonardo's vulnerabilities and quirks beautifully. His performance balances Leonardo's endearingly awkward nature with his occasional arrogance and self-doubt. When two girls comment on his good looks – and he is, perhaps more than he realizes – his shy yet pleased blush is a delightful sight.

Tortorici's filmmaking captures the character's conflicting emotions, shifting between realistic scenes, fast-paced montages, and animated sequences as Leonardo explores different aspects of his identity. By the end of “Diciannove,” not much is resolved, just like in the transition from teenage years to adulthood. Leonardo may be preoccupied with exams, dating apps, and insecurities, but he still has time to make the most of his life.