CGC question re: age for testing

Is there a general age of a dog that is most likely to p$#@! the CGC? Our local dog obedience club indicated no younger than 1 year. My pup is almost 8 months old and I was hoping to have him p$#@! it by March when he is a year old but hubby told me (somewhat in exasperation!) that it would be at least 18 months before my dog could p$#@! it. This got me thinking that as a pup goes through various stages of adolescence that maybe it is truly unlikely the would p$#@!. I realize there are many varying factors... how much you work with the dog with training and exercise, general temperament of each dog, etc. So, I'm just looking for a general idea and I know some of you have this experience based upon some posts that I've read.



Thanks!

CGC question re: age for testing