The five-time Ballon d'Or turned 36 in February but has shown no signs of slowing down after leading Juventus to another Serie A title with 31 goals.
Ronaldo has been in fine form this campaign, as he sits top the Serie A scoring charts with an impressive 12 goals in 11 goals.
The Portugal international did not give any specific age to retire, but he says he is feeling good at the moment.
"It doesn't matter the age. What is important is the mind," Ronaldo told BBC Sport.
"It doesn't matter if Cristiano Ronaldo is good, you don't know tomorrow what is going to happen. I live in the present, in the moment.
"The moment is good, I feel happy, I feel sharp and in a good moment in my life. I hope to play many, many years more but you never know."
Ronaldo was speaking at the Global Soccer Awards, where he was voted Player of the Century ahead of FC Barcelona's Lionel Messi.