Over the course of 12 seasons of being on air, Grey’s Anatomy has seen many of its fictional doctors leave the show. But while there’s been many cast shakeups over the last 11 years the show has been on the air, there’s been one permanent mainstay who doesn’t seem to be leaving the show anytime soon. In an interview with People, star Ellen Pompeo, who plays Meredith Grey, said there’s one main reason she’s not leaving the show: her age.

“My decision to stay on Grey’s was based solely on age. At 33, I was wise enough to know my clock was already ticking in Hollywood.”

Pompeo says she got a late start in Hollywood as she started acting in her mid-20s and said that if she had been younger when she started on Grey’s Anatomy, she would have done the show for a few years and then left to find other roles.

But now, Pompeo has no regrets about staying on Grey’s Anatomy, saying that “I thought, ‘Why would I leave something that is super successful and pays me great to search the landscape?’ I decided that I would stay on Grey’s and be grateful and try to ride it out for as long as I could. And I am very happy that I made the decision to stay. It’s only gotten better with time.”

And Pompeo’s right about Grey’s Anatomy getting better with time. After a shocking surprise in season 11 where leading man Patrick Dempsey was killed off, the show went through a renaissance in season 12 and finished as ABC’s top rated drama last season, something rarely heard of for a show in its 12th season.

For now, fans have little to worry about with Pompeo returning, as she signed a new contract for the show back in June, ensuring that she’ll be on the show for at least another year, as will other stars Justin Chambers (Alex Karev), James Pickens Jr. (Richard Webber), Chandra Wilson (Miranda Bailey) and Kevin McKidd (Owen Hunt) are returning to the show after the shocking exit of  Sara Ramirez (Callie Torres) in the season 12 finale.

Pompeo, Chambers, Pickens Jr. and Wilson are the only original cast members still on the show.

As for watching older episodes of Grey’s Anatomy, Pompeo tries to avoid them because she says it’s “miserable” to see herself aging on screen.

Grey’s Anatomy returns for its 13th season on Thursday, Sept. 22 at 8 p.m. Catch up on season 12 before the start of the new season, as it’s now streaming on Netflix.