You can solo gliders at 14 in Canada as our club has. And you can get your glider license at 16. There's lots of clubs in Canada as well as the Air Cadets. Our club runs during the week on good days and you can mow the runways on the poor days
Instruction is mostly weekends and two evenings midweek.
Once you meet license standards, even if you're below 16, you could move on to your Bronze Badge for cross-country qualification and then go for your Silver.
Check
Soaring Association of Canada - Home for glider clubs and pm me for details on our club.
I would suggest you first get some instructional flights near home to the point where your instructors think your coming to Canada for the Summer would be a good plan.