No matter how old you were, where you lived or how many T-shirts and mixtapes you owned, it’s unlikely that you remember the mid-1990s as well — as obsessively, as nostalgically, as literally — as Mid90s does. Written and directed by Jonah Hill, this film wants to be less a period piece than a time capsule, an immersion in the sights and sound of a pop-cultural moment.And even, almost, the smells. After Stevie (Sunny Suljic) smokes his first mentholated cigarette, he darts into a gas station men’s room on his way home, chugs some liquid soap straight from the bottle and fumigates his clothes with a cloud of air freshener. Stevie, whose coming-of-age story this is, lives with his brooding, violent-tempered older brother, Ian (Lucas Hedges), and their beleaguered single mom, Dabney (Katherine Waterston), in a modest house in Los Angeles. He’s a small guy, on the cusp of puberty, with wide blue eyes and a smile that undercuts his determined efforts to seem tough.At first, Stevie worships Ian, whose interests are hip-hop, street fashion and orange juice. Ian returns his younger brother’s admiration with sullen silence or brutality — the first shot of the film is of a beating that leaves a nasty bruise on Stevie’s chest. Soon enough, he finds new idols among a group of bigger kids who hang out at a skateboard shop, and he makes it his project to fit in with them.Mid90s winds its loose, episodic way through their rituals and routines as they skate, smoke, chase girls and talk nonsense. Stevie acquires a nickname — Sunburn, in honor of a half-clever joke he manages to blurt out during his informal initiation — and racks up rites of passage. First cigarette, first kiss, first “time in a car without someone’s parents.” It’s sweet, but also raw. There’s an undercurrent of danger and desperation in his new crowd, and you might find yourself worrying about Stevie even as you revel, vicariously, in his newfound pleasures.Like its hero, Mid90s struggles to figure out what it wants to be, and the struggle makes it interesting as well as occasionally frustrating. Hill, working with cinematographer Christopher Blauvelt, production designer Jahmin Assa, and composers Trent Reznor and Atticus Ross, aims for maximum authenticity of look, sound and language. The frame is boxy, the visual texture filmy and rough (it was shot on super 16 millimeter), the musical cues impeccably curated and the dialogue full of casual racism, misogyny and homophobia.Viewers who were around back then might remember Larry Clark’s “Kids” and other prurient, ostensibly cautionary tales of adolescent misbehavior. Hill’s sensibility is not so harsh, though — he’s a late 2010s guy at heart — and he filters some potentially ugly stuff through Stevie’s trusting, innocent eyes.The movie’s truest insights have to do with the hierarchies and rivalries within his new friendship group. Stevie is brought in by Ruben (Gio Galicia), who seems eager to have someone under him in the pecking order. He dispenses dubious wisdom along with smokes, and sells Stevie his old skateboard. But as the newbie starts to come out from under his mentor’s wing, Ruben gets jealous.There is also friction at the top. Ray (Na-kel Smith), the most talented skater and the leader of the pack, has ambitions beyond hanging out and getting high. This puts him in conflict with his sidekick (Olan Prenatt), a laid-back dude from a relatively privileged background whose nickname can’t be repeated here. Best friends since early childhood, the two are increasingly at odds in ways that threaten the harmonious vibes that hold the crew together. (The fifth member, known as Fourth Grade and played by Ryder McLaughlin, is the designated verbal punching bag and videographer.)For his part, Stevie might turn into a jerk or hold on to his openhearted, decent qualities. Beneath its posturing and profanity, Mid90s has some after-school special in its DNA, which I don’t mean as a knock. It’s a movie about making choices in tough circumstances, and for the most part Hill makes pretty good ones.