Sure, she's at the top of her game now, but Miranda Cosgrove hasn't always had success as an actor. "In second grade I auditioned to be a martian in a school play, and my voice didn't sound martian-y at all," Miranda says, laughing. "I got to be in the play, but I didn't get the part of the martian." Missing out on a dream role like that can be painful, but Miranda was having far more success as an earthling anyway—in 1996, 3-year-old Miranda got the okay from her parents, Tom and Chris, the owners of a dry-cleaning business, to sign up with a talent agent. Mere months after that she scored acting roles in TV commercials (for Mello Yello soda and McDonald's) and modeling gigs for Kmart and Bon Appetit magazine, and she was getting a lot of valuable practice navigating the casting process, even if things didn't always turn out her way. "I auditioned for a ton of things that I didn't get," she recalls. "But I never got upset about it. I thought it was fun doing the lines and going in and meeting other kids and stuff."

In 2002, 8-year-old Miranda was called in to audition for the Nickelodeon comedy Drake & Josh, starring actors Drake Bell and Josh Peck—she'd be playing the duo's troublemaker of a little sister, Megan. "I was definitely nervous, but all I cared about was meeting Drake and Josh," says Miranda, who knew the boys from an earlier Nick show. "But when I found out I got the part I was freaking out." At the same time, Miranda landed a role—as a know-it-all fifth grader turned band manager—opposite Jack Black in the 2003 feature film School of Rock. Soon after the movie came out, Drake & Josh premiered. "I was really popular at school at the time," Miranda laughs. "All the kids wanted to hang out with me. And then they realized, 'Oh, it's just Miranda.' " Of course, there was a downside to all that success. "I would go to school and then I'd go to set. Doing both at the same time got real confusing. Fifth grade was my last year. Sixth grade I left school with my friends and started working one-on-one with an on-set tutor."

That's a big change for a middle-schooler to make, Miranda admits. "I remember my dad saying, 'Are you sure you don't want to go to school?' " says Miranda. But she liked working on Drake & Josh so much that she felt she'd be missing out if she didn't keep doing the show.

When Drake & Josh ended in 2006, the show's creator, Dan Schneider, created iCarly especially for Miranda. "She's very mature and sophisticated in some ways," says Schneider. "And she's very little girl in other ways, and I just love that about her." Two years after its Fall 2007 premiere, iCarly is going stronger than ever—it's the highest rated live-action kids' program, and it set a series record this August when 7.9 million viewers tuned in to watch a special episode.

As for Miranda, she has more than proved to her folks that she made the right choice when opting for the set over school. This summer, just as iCarly was being nominated for an Emmy Award for Outstanding Children's Program, Miranda was getting inducted into the National Honor Society. "My mom is all excited about it, but I thought it was a rip-off because all I got was a pin," Miranda jokes. And if academic and TV accolades weren't enough, Miranda used this summer's iCarly break to work on a solo album and to record dialogue for Despicable Me, an animated film with Steve Carrell.

Currently 16, Miranda is starting to set her sights on college, but first she has two years of high school to complete with her tutor. And though she admits, "Sometimes when my friends have had an awesome day at school or they saw some guy they like, I'll be like, 'Oh, I didn't get to do that.' " Still, to her, it's all worth it. "I love acting so much that it outweighs the few things I don't get to do."