When the 20-year-old twisted her tongue, twerked and touched herself, social media went nuts; as the U.K.'s Mirror noted, young fans on Twitter branded Cyrus “scary, ” “embarrassing” and “disturbing.” Brooke Shields, who played Hannah's mom, weighed in, too: “I just want to know who's advising her.”

Cultural critics from Camille Paglia to Jody Rosen opened up their laptops, debating everything from whether the performance was degrading or empowering to Cyrus' sloppy use of African-American symbols. (Sasha Weiss wrote a good summary of that response in The New Yorker, also making the case that “Miley … in her spastic mayhem, anticipated the imminent online feeding frenzy. It was [as] if she were saying, ‘GIF me now.'”)

Less highfalutinly, the Mirror suggested that her “raunchy performance … sparked fears she will be the next American teen star to go into meltdown.” That puts her squarely in the company of Britney Spears, Mischa Barton and Amanda Bynes. All those stars had hugely successful brands as child and teen stars, only to trash them as they tried to grow up in public.

When your brand is based on being relentlessly wholesome, innocent and adorable, it's hard to transition into new brand attributes that suit a worldly, experienced adult. For girls becoming women, flaunting their sexuality is an easy way to show they aren't a little kid anymore—and a way that has historically (when used judiciously) enhanced women's likability. The problem is, it often backfires, especially when the girls go too far too fast.

Cyrus didn't help her case when she showed up “stumbling around, ” in the words of the Mirror, waiting to catch a private jet at New Jersey's Teterboro Airport sporting a cellphone, Chanel bag, goofy pajamas and fuzzy unicorn slippers. It was as if she was trying to be an innocent, wholesome little girl again. But it was too late—Pandora's secrets don't go back into the box—and she more than overcompensated with the outfit, which would have been weird on anyone older than 4.

Brooke Shields is onto something: Cyrus needs an intelligent adviser to help her get her brand back on track, stat.

She needs to find an equilibrium for her brand, one that's neither too sweet and innocent nor too scandalous and salacious. And she needs to do better than she has done so far, complaining to the Mirror that “I'm messed up…. I have so many f—ing issues…. I don't have a normal life. I take a hiatus every now and again, but I'm not good at that.” She told the same interviewer a few weeks earlier that she's a “workhorse” who “can sleep for just 45 minutes—I'm used to it.”

In other words, it's so hard being famous and successful. Cue the world's smallest violin. Plenty of young girls, teenagers and millennial women work just as hard without dressing like showgirls and twerking before an audience of millions.

Cyrus is no doubt hardworking, and there's no question that fame at age 14 can mess with a girl's head. But her VMA performance wasn't a matter of exhaustion or burnout. It was an attempt to slough off an outdated young brand with one that's much more outrageous.

As the New York Daily News put it, “Now that she's coming into her own womanhood, the ‘We Can't Stop' singer is going full throttle with her bad girl image and said that's more like who she is than any good girl persona previously portrayed on television.”

Cyrus has said that all along her Disneyfied brand was out of sync with her true identity. But now it's time for that brand to grow up along with her. The question is whether she can make it appealing and dignified at the same time.