No one emerges from the sprawling emotional minefield of adolescence without a few bruises and scars.

In that time of hormone-fuelled experimentation and startling self-realisation, when sexuality is wonderfully fluid, it’s important to stumble and fall – sometimes spectacularly – before nervously crossing the rubicon into adulthood.

Adapted from Phoebe Gloeckner’s 2002 graphic novel, The Diary Of A Teenage Girl elegantly documents a 15-year-old’s sprint through this minefield.

It does it without casting judgement on the morally flawed characters, or condemning them for their often provocative actions.

First-time writer-director Marielle Heller takes her aesthetic lead from the era (bell-bottomed 1976 San Francisco) and the visually arresting source material.

She bleaches her colour palette to resemble a washed-out instamatic camera print and visualises the heroine’s day dreams as animated sequences – courtesy of artist Sara Gunnarsdottir – that occasionally blossom within the live action.

These risky stylistic ambitions could have been Heller’s downfall, but there’s charm and purpose in the amalgamation of filmmaking styles.

The writer-director is aided by an excellent cast.

It’s led by British rising star Bel Powley, who sports a flawless American accent and exposes herself – figuratively and literally – to the camera for close scrutiny.

It’s a far cry from her comical turn as a plummy Princess Margaret in the recent A Royal Night Out.

“I had sex today,” gushes 15-year-old Minnie Goetze (Powley), recording the first chapter of an audio diary onto cassettes, which she hides in a shoebox under her bed.

As Minnie breathlessly details events leading up to the loss of her virginity, we realise with a shudder that her first sexual partner is her mother’s 35-year-old boyfriend, Monroe (Alexander Skarsgard).

“I was afraid to pass up the chance because I may never have another,” confesses Minnie without a hint of self-deception.

Monroe becomes enslaved to Minnie, who embraces her burgeoning sexuality in the company of a rich kid fellow student (Austin Lyon), a pretty lesbian (Margarita Levieva) and her best friend Kimmie (Madeleine Waters).

When Minnie’s bohemian, drug-snorting mom (Kristen Wiig) discovers the illegal relationship, Heller navigates the fallout with considerable flair and sensitivity.

The Diary Of A Teenage Girl is anchored by Powell’s luminous portrayal of a bud waiting to bloom in the warmth of the northern California sun.

There’s a beautiful scene early in the film when she stands in front of a mirror and traces the contours of her naked body, while wondering, “What’s the point of living if nobody loves you, nobody sees you, nobody touches you?”

Her heroine’s sense of fateful curiosity infuses every artful frame, catalysing terrific scenes with Wiig and Skarsgard, who lends his divisive character an easygoing charm and fallibility. Wry humour cuts through the potentially sensationalist subject matter, allowing us to view the storm through Minnie’s wide eyes before the tears well and fall.

The Diary Of A Teenage Girl (18, 102 mins)
Drama/Comedy/Romance.
Bel Powley, Alexander Skarsgard, Kristen Wiig, Christopher Meloni, Madeleine Waters, Abby Wait, Margarita Levieva, Quinn Nagle, Austin Lyon. 8/10