Ellen Pompeo Reveals the 'Toughest Part' of Starring in 'Grey's Anatomy'

— -- Ellen Pompeo has had a lengthy run as Meredith Grey on "Grey's Anatomy."

One reason she remains on the ABC medical drama? Her age.

"At 33, I was wise enough to know my clock was already ticking in Hollywood," the actress told PeopleStyle.

Pompeo said she had a "super late start" in launching her acting career, and that if she'd been younger when she began her stint on "Grey's", “I probably would have done my time, then gone out to search for other things.”

But as time went on, she was "definitely aware of how challenging it would be to find other roles in my late thirties and early forties,” she explained.

That's not to say Pompeo, 46, has regretted sticking with her star role on the series, which enters its 13th season this fall.

“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," she said. "I am very happy that I made the decision to stay. It’s only gotten better with time.”

The one downside, she said, has been watching herself age on TV.

"To be honest, it’s the toughest part of my job,” she said. “But as uncomfortable as watching myself age is, I don’t think focusing on physical beauty is necessarily the best thing for your mind. It’s a natural thing that we all do, but I don’t think it’s the healthiest thing. The older you get, the more you realize life isn’t about your looks. Everyone ages, and it’s okay.”