Vega was confirmed as the lead role in Helix, written and directed by Aram Rappaport, which began filming in Chicago in March 2008. She completed filming Repo! The Genetic Opera, which was released in 2008. In 2006, she starred in another made-for-TV movie, Walkout and finished filming Remember the Daze, which was released in limited theaters in April 2007. The following year, she starred in the Lifetime television film Odd Girl Out, as a victim of cyber-bullying. In 2004, Vega finished filming two films: Sleepover and State's Evidence. She was named one of the year's hottest teen celebrities in the July 2003 issue Vanity Fair.

Vega speaking during a Repo! Road Tour, 2009

In 2011, Vega appeared in the sequel, Spy Kids: All the Time in the World, as a grown Carmen Cortez. During the shooting of the three films she performed most of her own stunts. The first Spy Kids film was a huge success, and two sequels, Spy Kids 2: The Island of Lost Dreams and Spy Kids 3-D: Game Over were filmed. She became known worldwide in 2001 for her role as ' Carmen Cortez' in Spy Kids. She guest-starred in numerous television shows and films, including ER, Follow the Stars Home, Ghost Whisperer, and The Bernie Mac Show.

In 1996, Vega starred as young Jo Harding in Twister.

She moved with her family to California when she was four years old. Vega has six siblings, including actress Makenzie Vega. Her father, Baruch Vega, is a Colombian fashion photographer and student informer for the Central Intelligence Agency, and her mother, Gina Rue, is a former model. She spent some of her childhood years on a ranch in Ocala, Florida.

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