A new promo shows a nervous Jenner getting ready for his big 20/20 interview

For Bruce Jenner, the future is largely unknown.

“I want to know how this story ends. How does my story end?” the former Olympic champion, 65, says in a new promo for his much-anticipated 20/20 interview with Diane Sawyer, airing Friday night, about his decision to transition to a woman.

In the promo, Jenner is clearly nervous to sit down with Sawyer and talk about such a personal decision.

“It’s going to be an emotional roller coaster, but somehow I’m going to get through it,” he tells her.

Echoing an earlier promo, he also mentions his family and his worries about the impact on them. “Those are the only ones I’m concerned with,” he says. “I can’t let myself hurt them.”

The 20/20 interview will be the first time Jenner has spoken publicly about his journey.

Bruce Jenner – The Interview airs Friday at 9 p.m. ET on ABC.