you have to be 18 to buy real airsoft guns in ontario. This is why people are telling you to be AVed, you need to prove that you are 18 to the community before they will tell you where you can get the good guns.
The guns at canadian tire and walmart are not airsoft guns, they are clear and are closer to toys in how they are treated by the law. Real airsoft guns, because they are black and full metal are treated as real guns by the police if they see you with one. That's why it's important to be of proper age of maturity to buy one.
Since you're so close to being 18, I would spend the next few months reading up on airsoft so you know what's good quality stuff and what's junk, and what's a good deal, what isn't a good deal. You can also start buying some of the safety equipment... goggles/mask and boots, etc.