Minors less than 18 years old and citizenship

I had sponsored my wife and son and both got their PRs July 2017. My question is concerning my son who is 14 years old. Does he have to wait for (complete) three years before he can apply for the citizenship? Or, he can apply for it right now since he is only 14 years old.
Thanks in advance for any information.
Thanks for the information. I am already a Canadian citizen, but my son was born before I became a Canadian citizen. For this reason I had to sponsor him.