Selena Gomez flashes her string-of-pearls smile and black-olive eyes as 3,000 fans give her a rock-star welcome Monday at the King of Prussia Mall.

The sound of Selenamania is an earsplitting squawk, something like that of squadrons of overexcited seagulls. Gomez, the recording sensation, star of the Disney TV series The Wizards of Waverly Place, and anchor of the Fox mistaken-identity comedy Monte Carlo (opening Friday), is buoyed by the shout-out.

With self-assurance and self-doubt in dizzyingly equal proportions, Gomez, 18, is walking the tightrope from teen idol toward mature stardom in five-inch heels, struggling against the perception she's just a "Disney girl."

You can count on one hand the number of child stars who have made it across. Elizabeth Taylor. Natalie Wood. Jodie Foster. Leonardo DiCaprio. Christian Bale.

If fan love alone were all it required, Gomez would be there already. The adulation helps her keep balance on the tightrope. Working in her favor is that the person she is in front of thousands of diehards is the same one she is in a one-on-one.

"We love you, Selena!" shrieks Erin Daly, 12, of Aston, who with friends Shannon Savage, 13, and Adelina Alvarez, 12, arrived at the mall at 4 a.m. They have patiently waited 14 hours to see the thrush whom Daly calls "my role model."

Selenamaniacs know every word to "Who Says," the singer's platinum-selling empowerment anthem about not letting the bullies define you. They buy her Dream Out Loud clothing line (sold at K-Mart, not at pricey mall boutiques). They are Facebook friends of the girl who calls Justin Bieber her boyfriend.

"Girls relate to her," says Erin Siminoff, vice president of production at Fox 2000, producer of Monte Carlo. "They want to be her. She has an accessibility and a sophistication."

"She's a sweetheart to her fans," says Colette Villas, 17, of Newtown Square.

Some of her biggest fans are fan moms.

Sarah Freymoyer, managing editor of the website www.phillyburbmoms.com, speaks for them when she enumerates Reasons to Love Selena: "Her songs have positive messages; she's wholesome; she covers herself up when she dresses."

"My daughter started out as a Miley Cyrus fan," Freymoyer says of the onetime star of Disney's Hannah Montana. "But then Miley spiraled down so quickly."

As have so many other Disney alumnae such as Britney Spears, Lindsay Lohan, Christina Aguilera and Vanessa Hudgens.

In Hollywood, the post-Mouse House career death spiral is known as The Disney Curse. Gomez prefers to see it as a stigma that can be overcome.

Tricky thing, a young star's career.

Coltish is OK for tweens and teens. But if you're a teen powerhouse who wants a career beyond the Disney/Nickelodeon stable, how do you show you're maturing without taking your clothes off?

"I come from Disney World and am not taken seriously," Gomez explains matter-of-factly Monday afternoon before her triumph at the mall. She sports a metallic-gold cardigan over a pink linen shirt and black jeggings. Her ensemble says "casual fun." Her pearlescent white stilettos say the opposite.

"It doesn't feel good to be rejected, to hear that directors want Mila Kunis, not a Disney girl."

Disney girl? "The perception is of somebody who probably overacts, probably has no sincerity, probably thinks of acting as a job rather than a skill," says the trouper who treasures her Disney experience. Gomez regards the cast of the Wizards of Waverly Place - which will air its fourth and final season this fall - "as my second family."

Talking about filming the last episodes makes her eyes well up. "It inspires me when moms tell me they want their girls to be sassy and stand up for what they believe in, like [her Wizards character] Alex."

Gomez deals with "the negativity and rejection" that she faces from casting agents and from the haters on Facebook the old-fashioned way - with affirmations.

"I live by inspirational quotes," she says. Favorites are "You are who you surround yourself with" and "This, too, shall pass." Fox 2000's Siminoff admires Gomez's professionalism and "incredible work ethic."

Recently she fainted after an appearance on The Tonight Show With Jay Leno, prompting rampant Internet rumors of pregnancy and anorexia. The culprit was junk food, she admits. "I'm 18 and I'm stubborn. They offer me healthy home-cooked meals of lemon chicken and zucchini and cheesecake, but I want Taco Bell."

She has a cracked-walnut voice, throaty and playful. She was named for Tejano singer Selena Quintanilla and grew up dancing to "Baila esta Cumbia." Those of a certain age remember Gomez as Gianna, the amiga on Barney and Friends. Now it can be told, she says: "That guy in the purple suit was really cute."

"When I was nine doing Barney, I was picked on by kids in school for doing a baby show," Gomez says with a sigh. "It's such a funny thing, how nothing's funny when it's you," go the lyrics to Gomez's "Who Says," her epically relatable song about bouncing back from put-downs.

After Barney, she did some Disney shows before ultimately getting cast in Wizards at 14. Gomez dated Nick Jonas of the Jonas Brothers and Taylor Lautner (Twilight's Jacob) before keeping company with pop sensation Justin Bieber. Like him, Gomez was raised by a mother who gave birth to her when she was a teenager.

How does Gomez know she's in love? "For me, it's when I feel most beautiful and I laugh so hard my stomach hurts."

When designers approached her to launch her Dream Out Loud line of clothing, Gomez was psyched. She had recently met a young fan who used a paparazzi photo to replicate her tousled-Boho look. "I was so honored," she says. "I'm very casual," she says. "I wear things that are simple and trend-free. My job requires me to be in hair and makeup a lot. When I don't have to dress up, I don't."

Since being an actress/singer/entrepreneur isn't demanding enough, Gomez signed on as a UNICEF Goodwill ambassador. Her 2010 trip to Ghana was an eye-opener. "So many kids in America say 'I hate school, I hate homework.' The kids in Ghana want to go to school, want homework, want to learn." If she had the power, she says, "I'd build schools in Ghana."

While her own songs are for the most part mood-elevating, Gomez isn't the type of music lover who uses songs to lift her spirits. "I'm a very morbid person. When I'm sad, I want to be sad. I'll listen to Death Cab for Cutie or 'More Like Her' by Miranda Lambert."

Gomez's edge in Ramona and Beezus and in Monte Carlo, where she has a dual role as a down-home Texas girl mistaken for a spoiled heiress, distinguishes her from the sunshine overdrive of many teen stars. "In Ramona and Beezus, we saw this other side to her," observes Siminoff, who is betting that Gomez has the resources to play three-dimensional characters.

The actress hopes her next movie project will be 13 Reasons Why, based on the novel about the aftermath of teen suicide.

"It's not a Disney choice," she admits. "But I found it very inspirational.

"Not everything is a happy ending," Gomez reflects. "Sometimes it can be a life-changing one."

For a video of Selena Gomez greeting her local fans, go to www.philly.com/

selenaEndText