Speaking with PEOPLE ahead of the last week of season 16, Cowell gave an update on his health while applauding all the contestants this year, explaining that the acts and the production crew exceeded his expectations in yet another season during the ongoing COVID-19 pandemic.
"I feel a lot better actually. I think the good thing about the accident is that you got to do a lot of exercises, all that kind of basic stuff. I'm doing more exercise now before the accident. So weirdly, I feel better than I did before I broke my back," Cowell, 61, says of recovering from his August 2020 fall off an electric bicycle which resulted in a metal rod put in his back during a five-hour surgery. "For me, it worked out fine. I mean, it hurts occasionally. But it's not a big deal."
Explaining his excitement about returning to judge a variety of acts after being out last season, the father of one says he's continually in awe of the "incredible stories" about pushing through adversity.
"I was expecting a lot of people to be very down for obvious reasons. But it was the opposite," Cowell says, referencing the global health crisis. "It was like, 'No, we've come through the pandemic and this is really given us something to look forward to.' As always, on these shows, you've had these incredible stories. Whether it was Archie [Williams] last year, whether it was Kodi [Lee]. This year, of course, Jane [Marczewski, who performs under the name Nightbirde]."
This season, Cowell chose Nightbirde as his Golden Buzzer winner after she gave a standout audition with her original song "It's OK," which is about her life and fight with cancer. In August, the Zanesville, Ohio, native announced on social media that her health took a "turn for the worse" and she was no longer able to compete.
Trae Patton/NBC Nightbirde
"Unfortunately, she is really ill and could not make the finals. However, it was always her dream for her music to be heard by millions. That's what's happened off the back of this," Cowell says of her AGT audition.
"We talk about once every two weeks. It was a difficult conversation we had about does she enter the show or not. I know that she was very down. I called her and I said that, 'Honestly if I was in your position, I wouldn't do it.' Because you don't need the stress right now. It's just not worth it," he recalls.
"You can always re-enter the show or you don't have to because, at this point, when you put your music out, I think a lot of people are going to buy it. So why put yourself through it," Cowell remembers telling Nightbirde. "You're not letting anyone down because that's what she kept saying to me. You're not, you're going to be missed but you're not letting anyone down."
During the live shows in August, Nightbirde shared an emotional moment with Cowell when she made a virtual appearance when she thanked the judges and fans for the overwhelming amount of support she received, which she said "restored my faith in humanity."
"You made the decision, rightly so, that your health is your priority right now ... Even though you haven't competed – you've already won," Cowell told the singer while holding back tears. "The most important thing is your well-being, your health and your recovery."
Looking ahead to Wednesday's results show and who could become the champion, Cowell already has a winner in mind.
"My choice would be Aidan [Bryant]. I think he's amazing at what he does. If it was me voting, he'd get my vote," the veteran judge shares.
Bryant, the 16-year-old self-taught aerialist, was previously called the "one to beat" by Cowell after his "gold medal-winning" semifinal performance. The Virginia teen is only in his second year of learning aerials after starting out in the backyard with a tree and a bedsheet.
Cowell also tells PEOPLE that he has full confidence in Bryant to headline his own show in Las Vegas.
"A million percent. If he can do that when he taught himself at 14 and he puts his mind to it. He's the kind of person you just believe he can do anything," he raves.
The season 16 champion will win a $1 million prize and residency at Luxor in Las Vegas.
Along with Bryant, the finalists competing include: singers Victory Brinker (all-cast Golden Buzzer winner), Jimmie Herrod (judge Sofia Vergara's Golden Buzzer winner) and Brooke Simpson as well as quick change artist Lea Kyle (judge Heidi Klum's Golden Buzzer winner), comedians Josh Blue and Gina Brillon, magician Dustin Tavella, World Taekwondo Demonstration Team (host Terry Crews' Golden Buzzer winner) and Northwell Health Nurse Choir (judge Howie Mandel's Golden Buzzer winner).
America's Got Talent airs Tuesday and Wednesday on NBC.