While she certainly celebrated turning 65 this year, it was Oprah Winfrey’s 57th birthday that turned out to be the most significant.

That’s because the talk show icon never expected to live past the age of 56. In this week’s issue of PEOPLE, the mogul and philanthropist opens up about the childhood dream that gripped her despite her success.

“I used to have this dream that I was going to be dead at 56, so the year that I turned 56 I was filled with dread,” Winfrey says. “I had only told one other person that I had a number in my head when I was going to die, and that was Gayle [King, her best friend]. Gayle said, ‘What’s the number?’ I said, ‘I’m not going to tell you, because you will drive me crazy and then I will end up dead.’”

In 2011, the year she ended her talk show, she finally exhaled.

“When I got to 57, it was like, ‘Why did all my life I think it was going to be 56?’” she says. “At the time I started having this vision of 56, it was when I was in Milwaukee and I was trapped in a world where I could see how dire it was.”

RUVEN AFANADOR

Winfrey also opens up about some of the moments that changed her life, including moving to Nashville to live with her father from her childhood home in Milwaukee as a teenager.

“When I was in Milwaukee, I was trapped in a world where I could see how dire it was,” she says. “Had I not gotten out of Milwaukee, nothing would have been the same. I do believe I would have been dead at 56. I believe I would have been 437 lbs. I believe I would have had diabetes. I would have had high blood pressure. I would have suffocated knowing that things could have been different.”