For a starlet with a record deal, one last season of her Disney Channel series ("Wizards of Waverly Place") and her own clothing line, Gomez puts a lot of effort into keeping things on the down-low.
Take her debut feature film. If you remember the Beverly Cleary novel about the misadventures of Ramona Quimby and the teen sister she still calls "Beezus," you'll remember the title was "Beezus and Ramona." The title was changed, and Gomez is taking second billing.
And even though she has movies in the can and more on her radar, don't think she's going the way of Miley Cyrus and Vanessa Hudgens just yet - fretting over that "transition" from child star to young adult.
"My mom doesn't want me to grew up too fast," she says of her mother and manager, Mandy Teefey. "I'm 18, but younger than that at heart. I'm not going to do anything that I'm not comfortable doing.
"I'm fully aware of my audience. I may hope and dream of having an older audience some day, for my film and TV work and my music. But now, the people who have been with me over the past four years are these 7- to 15-year-olds who have given me my job. If a little girl tells her mom, 'I want to see the new Selena Gomez movie' or 'buy the new Selena Gomez CD,' I would hope that their parents could say 'absolutely' without having to second-guess it or second-guess me.
"So there's a transition coming. I'm just not there yet."
In "Ramona and Beezus," Gomez plays Beatrice, 15, who is just getting interested in boys, something not helped by her "pest" of a little sister and the nickname she's had since her sibling couldn't pronounce her name as a toddler.
"I read the Ramona Quimby books in third and fourth grade. ... I fell in love with the character Ramona. When I heard about this project, I reread all of them because I really wanted to do it and see who I could play.
"But even though I could relate more to Ramona, especially at that age, Beezus looked like a fun character for me to play because of how different she is from me in real life. She's every awkward teenager, isn't she? Uncomfortable in her own skin, trying to figure out who she is, crushes, finding her place among her siblings.
"I love that the movie takes time to let Ramona watch her sister grow up and learn from it."
Something akin to that was happening off camera, where Gomez, an only child, got to have a "sister" for a couple of months.
"Ramona" to Gomez's "Beezus" is Joey King. They both started acting while very young, and Joey calls Gomez "a great role model. She's so humble, and I hope I can be like that when I'm her age."
Gomez is looking for role models, too. One is Rachel McAdams of "State of Play" and "The Time Traveler's Wife."
"I would love to model my career after hers," Gomez gushes. "She's brilliant. She chooses smart roles, reinvents herself for every role. I admire that and hope I'm able to do that myself in my career."
McAdams? She's 31, has 20-some TV and film credits. And she's never on TMZ.
"Oh, my goodness. That's why I love her!"