See, now there's the problem. Let me sort some things out for you:

1) You will have a real tough time finding someone to sell you an airsoft gun, since you are a minor. Most reputable places will only sell to people 18+.

2) Playing in your backyard is dumb. It will get you shot by the police. Think I'm kidding? Guess again....at 15 feet a police officer can't tell if these guns are real or fake. Due to the recent spree of gang shootings in the city, they will tend to shoot first and ask questions later.

3) It is illegal to import airsoft guns into Canada without some very specific permits. Those permits cost about $8000, and you have to be working in the movie industry to apply for them. I know this because I worked part-time in the movie industry.

4) If you do try and "sneak something by" Customs Canada, you will be caught. Getting caught means they sieze your brand new gun and destroy it. Getting caught also means you go are branded as a security threat and your name goes on a watchlist and EVERYTHING that is addressed to you from outside the country will be opened and inspected. Any time you cross the border, you are going to be harrassed by Customs agents because the database will list you as a known smuggler and security threat. I know this because my father is the former head (retired) of T2 Compliance Division at Canada Customs and Revenue.

Airsoft is not going anywhere. Come back in 2 or 3 years when you have a steady part-time job and can afford to get some decent gear. In the meantime, play paintball, a hobby that welcomes players under 18.