The air of an afterschool special hovers over Patricia Riggen’s tale of a precocious young girl trying to grow up too fast and her single mother, who needs to grow up faster. Earnest but forced, “Girl in Progress” has its heart in the right place, but is conspicuously short on brain power. It comes as a disappointment after director Patricia Riggen’s previous picture, “Under the Same Moon.”

Eva Mendez stars as Grace, a young woman whose teen daughter Ansiedad (Cierra Ramirez) is feeling a mite neglected and struggling to find herself. Grace works two jobs to make ends meet. She’s a jovial waitress in a crab shack, but to supplement her income cleans houses, most notably that of Dr. Harford (Matthew Modine), with whom she’s carrying on an affair right under his wife’s nose. Despite her responsibilities, she remains a sort of party girl at heart.

Ansiedad, seems mature for her age, as is shown by the comically blunt class report she delivers about her family life. (She also seems to have fashion sense—with a wardrobe that seems extravagant, given the financial strain they’re operating under.) When her teacher (Patricia Arquette) introduces the class to coming-of-age stories, she embarks on a project to go through all the traditional “rites of passage” they contain and, having grown up, go off on her own. That leads to such projects as dumping her best friend, chubby Tavita (Raini Rodriguez), to get in with the cool crowd (though she assures the girl it’s all an act), and having her first sexual encounter with the class hunk, Trevor (Landon Liboiron).

Meanwhile Grace has to deal with Harford’s duplicity after his wife finds out about them, as well as a crisis at work when scruffy busboy Mission (Eugenio Derbez), nicknamed Impossible, whom she’s promoted to the kitchen while temporarily in charge, steals from the owner’s safe in a misguided effort to help her out of a financial jam. And when the inevitable ramifications of her daughter’s unwise project strike home, she has to take action on that front as well.

The idea of juxtaposing the stories of a woman who made mistakes in her life and a daughter who might be making them in a different way is intriguing, but Hiram Martinez’s script doesn’t meld them with much success. The whole notion behind Ansiedad’s growing-up project frankly seems absurd for a kid who’s portrayed as being unusually bright, and the upshot of it leads to results—with both Tavita and Trevor—that have a Disney Channel feel (though the Trevor episode ends with a moment that has to be a homage to “Sixteen Candles”). And while Grace’s side of the narrative is less clumsy, the choice to posit a possible romance with Mission as an alternative to her destructive one with Harford is contrived.

Mendes gives her all to the role, going from Lucille Ball ditzy to deeply involved parent enthusiastically (indeed, at times too much so). Ramirez often seems affected, but that’s a function of the screenplay (and of the character’s being an adolescent). Modine is suitably unctuous, Arquette appropriately concerned, and Rodriguez a likable young Vivian Vance-like sidekick. Derbez, by contrast, overdoes the unlikely suitor bit.

It’s nice to see a Latino-flavored story set outside the usual southwestern locales—in this case in Seattle, and cinematographer Checco Varese takes fairly good advantage of the northern environment (though the picture was actually shot in Vancouver). But Christopher Lennertz’s score is generic, and the narration by Arquette that periodically punctuates the action is intrusive, italicizing obvious points in a fashion that suggests the makers consider some of the potential audience to be too dense to get the message on its own.

Given the potential of the premise, one wishes that “Girl in Progress” were better than it is. But Riggen’s film, like Ansiedad, remains rather juvenile despite its desire to deliver a mature message.