Just two years ago, Zion Harvey thought he'd never throw a baseball again.

The young boy had lost both his hands and legs after suffering an infection when he was a toddler. Today, a year and a half after he became the world's first child to have a double hand transplant, he says he's a new person.

NBC News has followed Zion's story each step of the way from his surgery to recovery. All the grueling therapy has paid off, his mother Pattie told NBC News.

"It's like a fairy tale for me," said Pattie. "My son got hands, and I'm the richest woman in the world now."

Zion's surgeon, Dr. Scott Levin, chairman of Orthopedic Surgery at the University of Pennsylvania and director of the Hand Transplant Program, said Zion's nerves have now grown into the transplant part of his hands.

"Even those fine muscles that are responsible for fine motor movements are now functioning," Dr. Levin told NBC News.

It has been a whirlwind year in the spotlight for 9-year-old Zion. Support has poured in from all corners since his story first aired on "NBC Nightly News with Lester Holt," including from former President Bill Clinton who sent him a letter.

"Your mom is a warrior! Mine was too. Hold on to her," the former president wrote Zion.

For Pattie, who gave Zion one of her kidneys even before the hand transplant, the journey has been a long one. She and Zion are writing a book about their harrowing experience.

"Just gonna talk about how me and other people with prosthetics and disabilities have a different kind of relationship," said Zion. "We all have a story."