The 33-year-old ended his illustrious nine-year stay at Real Madrid on July 10 by penning a four-year deal with the Serie A champions for a fee understood to be £105m.
Some fans and pundits are wondering whether Ronaldo can still continue at the highest level despite being in the twilight of his career, but the Portugal icon is not worried about the issue.
"I'm very well physically, mentally and emotionally so that's why I'm so proud of being here and of the way I came here," Ronaldo told reporters at his presentation on Monday. "It gives me so much motivation for the future.
"I'm different from all the other players that think their career is over at my age. The age is not important, I feel good, I feel motivated, excited.
"I really want to show I'm not like the others, I'm different, it's a very emotional moment for me and the club because I'm not 23, I'm 33."
The five-time Ballon d'Or winner arrives at Juventus on the back of four Champions League titles in five years with Real.