Hello,
I'm not in the CF (yet, I suppose) but my experience is quite similar to yours.
I was recently offered to join the CF (Army) after a relatively short time in the recruiting process. I have used marijuana in the past (five years prior to my declaring it to the recruiter) and only had one job before joining. So, I can tell you that it is certainly possible.
With that said, I have been under the impression that the military wants there to be more than a few months of non-usage before you declare it to them. Not sure how many (I have heard 6 months) or if it's even true. Even if it isn't, smoking up the day before your interview or medical isn't a good idea. Best to get used to not using drugs now. And to your credit, it sounds like you have.
I'm willing to bet that at least 40% of the population, and I believe that's a conservative estimate, has tried marijuana at least once in their lives. The CF would have a significantly diminished recruiting pool if they outright banned people who have used it from joining up. What they do want, however, is commitment to their policy of non-usage. Make it clear to them when asked about drugs that you are not interested in further use. It's what I did.
Best of luck!