I started my Golden boy at 6 yrs old and it was the greatest experience. My current trainer is a Karen Pryor trainer and quoted her once as saying "can every dog be trained with every method? No. Can every dog be trained with a clicker? Yes." For some reason that just stuck with me. I think it's true for almost all animals including fish, elephants, horses, goats, and many other species you see many problem solving things on animal planet with so many animals where a problem exists that has so far been insurmountable. That speaks a lot to me. The fact that at the very most it can do no harm is great. Positive training never has warnings or disclaimers with it for a reason.
If my 6yo boy could get his CGC, learn agility, rally, obedience, and all the other great things he enjoyed any dog can. I bet you'll really enjoy all the things you can do once you give it a try. I have to admit I was a bit dubious standing in my first ever dog class and being handed a clicker. Coming from a traditional training background, I always had good dogs. When I started using the clicker I found a new world of possibilities and incredible detail opened up for me. The two dogs I have now can do the most awesome things. Many times I click random behavior I see and come up with some real doozies. Both girls now know how to hike their back legs for me to wipe their rather furry undercarriage after potty. I just say tripod. Of course they will also do it for belly rubs.
I also used a clicker for a super scared foster dog that was totally shut down. The tricks she learned after being neglected her entire life are what gave her confidence and made her new mom and dad fall in love. :dogtongue2: