Tyler,
Here's the basic breakdowns of what it takes to be perceived as a successful individual and businessman, even @ age 17. I know because I was working for a major dot-com developer at that age, and more than 1 client dropped their jaw when they saw me at that age walk in to the conference room.
- Convey professionalism throughout EVERY interaction. This means - don't add slang on to your conversations ("What's up dude?"), write every email carefully and with NO instant messenger shorthand ("I will find this out and BRB"), and make sure all background distractions are off or shut out ("Oh, sorry, that noise in the background is my girlfriend is watching MTV right now"). Sadly, remove as much personality from your interactions until your client understands that you're a PROFESSIONAL first and your age is irrelevant.
- Create high quality identity products - business cards, letterhead (both digital and print), envelopes, brochures, marketing materials, etc. Spend a significant amount of time on these materials, because oftentimes someone will interact with your logo or brand before they interact with you. If it's a crappy presentation, it will reflect on you directly. Also, create a high quality voicemail prompt, and be sure to have a separate line that your clients call versus your friends. It should be something along the lines of "Thank you for calling Tyler [lastname] of [company name]. I'm sorry I can't take your call, but if you'd leave your name and number, and a brief message I will return your call as soon as possible." No gimmicks, no bullshit.
- You have to act "as if". If you don't know what that means, go watch the movie Boiler Room. Act "as if" you're a 35 year old veteran designer, and your clients (especially over the phone) will perceive that - without asking you. Act "as if" you've worked on thousands of projects just like theirs. This isn't really lying, it's simply not offerring up any clues during a phone call that you're younger than they think you are (or ought to be).
- Honesty is huge. If someone does ask you how old you are, answer them. If you are in over your head on a project, admit as much. That's probably the biggest failure a younger entrepreneur has versus an older one. An older one has already learned that a client appreciates truth rather than sporadic delays and setbacks.
- Write formal proposals & agreements for everything. In this regard, you might want to consider a lawyer, but only if you think that it's actually necessary (ie, your client seems like a stickler). In most cases, you'll be fine if you simply outline the project ahead of time, including time & cost estimates, and then send it to them as a PDF in your company letterhead. The front page should be a title page, the 2nd+ page should be the description of the project, the second to last page should be a complete cost & time breakdown, and the final page should be a client agreement. The client agreement should be signed by you before you send it to them, and if they approve the project as outlined, they simply sign it and fax it back to you. Oh yeah, get an eFax.
- Recognize the fact that yes, some people will not be able to see past your age and won't want to hire you. Don't fight too many battles up hill, you'll get jaded. Pick some low-hanging fruit to start off with, and ALWAYS ask your satisfied clients for referrals. For most people in your situation, after a year of business you probably won't even need to market yourself - your clients will be buzzing with positive things to say about you whenever anyone asks "hey, do you know anyone that can do XYZ?"
In terms of being a cannuk, I have no idea what it takes or what is different versus setting up a business in California. In CA it's pretty straightforward - you get a business license from your local city hall, file a DBA with your county clerk and newspaper, and inform the IRS that you're establishing a business to request an EIN. At that point, with your DBA completed you can setup a bank account and the business can send and receive funds separately from your personal accounts. Like I said, I have no idea what is the same or different about that process in Canada vs. America. I DO know that in most instances in America, you have to be 18 to sign a legally binding contract, however there are exceptions, and even then you can use your parents or older sibling or trusted older 3rd party proxy to do some of those things for you.
Good luck man. Try lots of techniques and see what works best for you, and continue to look at the big picture and the long-term prospects.