First thing is how old you are. If you're 18+ then make arrangements to meet with an age verifier. You'll then have access to the classifieds and retailer sections of the forum where you'll have a cornucopia of guns available to you. And don't get airsoft guns from Cdn Tire or Walmart. Those are nothing but junk. The only worthy airsoft gun either of those places sell is the shotgun you can get at Walmart. It's clear plastic, but actually a damn decent performer for the money.
If you're under 18, then you shouldn't own air guns (pellet or airsoft) anyway.
As for a teacher, do a lot of reading on these forums. It's a goldmine of information.