To get ready for this year's big show, let's rewind to a time when today's biggest superstars were a bit more baby-faced.
In 1999, Britney was brand new on the scene, and the 17-year-old was giddy about performing a medley of her singles "Sometimes" and "Crazy" in front of the screaming crowd.
"I'm always nervous before I perform so, but it's a good nervous energy," Britney told ET at the time.
She also opened up about her meteoric rise to fame, explaining, "Everything happened so fast. I'm just taking it one day at a time but I'm having the time of my life."
In 2008, another young entertainer was still getting used to the idea of superstardom. Sixteen-year-old Selena spoke with ET, and opened up about how strange it felt to be in the media spotlight.
"It's a little weird, being 16 and going outside and wanting to have breakfast with my family and there's paparazzi following us, it's a little weird," Selena admitted. "But it's something I guess that I'm gonna get used to."
For Kendall Jenner, being in front of the cameras wasn't anything new even when she was younger. At the 2010 awards show, a 14-year-old Kendall opened up about dealing with criticism over a bikini-clad photo shoot some felt was inappropriate.
"I'm not really focusing too much on what people are saying," Kendall explained. "I'm almost ignoring it because I'm happy with my photos. I don't regret them at all."
Seeing how her career in modeling has flourished, it seems Kendall's persistence paid off for her.
Check out the Teen Choice Awards this Sunday at 8/7c on Fox.
ET: Before They Were Famous is available on newsstands and at OnNewsstandsNow.com