To some, she is striking the latest blow for female equality; to others she's refusing to grow up. Meet the "woman-child", emerging as a powerful new demographic thanks to her desire to relive her youth.
Retailers, TV bosses, publishers and film directors are rushing to cater for the new breed, epitomised by the 32-year-old actress Zooey Deschanel. Sky is hoping its latest US import, the HBO comedy Girls, will resonate with this audience when it airs next month despite featuring women in their early twenties.
And Hollywood producers are lining up big-budget films with "woman-child"-friendly plots, such as Ass Backwards, starring Alicia Silverstone in a story about two best friends who return to their home town to attempt to win a pageant that eluded them as teenagers.
Deborah Schoeneman, one of the writers on Girls, said the series was aimed at women "who seem to be acting and dressing like girls more than ever". The "woman-child", a term Ms Schoeneman uses in a new book, is an "increasingly powerful breed of pop-culture female who seems to be ageing backwards", she added.
Older women are helping to drive sales of "young adult" novels, which range from Suzanne Collins's The Hunger Games series to Cassandra Clare's urban fantasies. Sales of young adult fiction soared by 26 per cent in the first half of the year, with 2.4 million titles sold, Nielsen BookScan data showed.
Ms Schoeneman says: "It's a hot fashion trend popular with celebrities like Katy Perry, Zooey Deschanel and Nicki Minaj. Plus I think the recession also made a lot of women move back into their parents' homes and delayed them starting the career they wanted. Advances in fertility treatments have also made it easier for women to delay having children. Women are increasingly their own bosses as they shatter various glass ceilings, so they can dress however they want instead of trying to blend into a man's business world."
The fashion designers Henry Holland, Phillip Lim, Louise Gray and Meadham & Kirchhoff are among those driving the trend, with heart-splattered dresses, owl-motif jumpers and cartoon caper prints all selling strongly this season.
Annie Auerbach, director of trends and foresight at the consultancy Flamingo, said the new expression of femininity suggested that women have more confidence. "They aren't reliant on aping masculinity." She said this could have wider social repercussions. "Unashamedly liking very girly culture might be part of a broader thing of society placing more value on feminine traits."
Vivienne DaCosta, 41, a mother of two teenage girls and a reviewer of young adult novels, said part of the attraction was escapism. "Reading young adult books allows you to step back into a time where you had very few real life issues to deal with."
In the UK, figures for 2010 show the average age for women to get married hit 30, up from 22 in 1970, while women are waiting until they are 29.5, on average, to have their first child. Nearly half of all babies born in 2010 were to mothers aged 30 and over.
Ellie Levenson, author of The Noughtie Girl's Guide to Feminism, said criticism of women acting younger than their years was "just ageism". She said: "If a book is good, or a series funny, or a look is fun, why shouldn't it be for all ages? It's basically misogyny, telling women what they should wear and how they should act."