If you do join and the Canadian military is anything like the US one, just be prepared to do anything, even if it is out of your job description.
If you go in as an officer after college (again not sure if Canada has the whole commissioning thing after college) try to see things from the enlisted side. It will save you a lot of grief.
Had an officer bitch me out for not wearing seat belt cutters on my IOTV when we were in vehicles that didn't have operable seat belts. Needless to say, I never listened to a damn word he said after that. Don't be that guy that has book smarts but no common sense. If you go enlisted with college you'll promote faster but still have to embrace the suck early on in your career and will likely be held to a higher standard because of your advanced maturity level and non retard nature.