I have not been filing my taxes and it wasn't a real concern to me until now. I now know how serious it is and I messed up. I have never filed before and I do not know where to begin. I don't know where I can get this info from. I'm in another country too. I'm trying to get my T4s but I'm not sure how or where to send them. I turned 18 in 2007 but only worked half of that year in Tim Horton's, I am not sure if that counts since I was still in high school. What should I do to fix this?
It's time to hire an accountant who specialises in this sort of thing. That is, an accountant who specialises in Canadian tax. Do not go to a tax filing service such as H&R Block, as you need more help than that. You may also wish to consult a lawyer, but that's probably not necessary at this time, provided you are able to pay any owing taxes and penalties.
Working at Tim Horton's in 2007 definitely counts. You earned income and then did not file a tax return. Note that it is possible that you owe nothing at all, and may even be due a refund for taxes paid. If that is the case, this may be much easier to resolve than you expect.
If you have not been living in Canada and not earning income in Canada, there's a good chance you don't need to file any tax returns for any year you have missed (compare this with being a U.S. citizen). Again, though, it's time to hire an accountant to figure this out with certainty.
In summary, you do need to talk to a real accountant. But it's very likely not as bad as you think it is. Plus, my experience with the Canada Revenue Agency is that they are very polite and easy to deal with, so long as they are going to get their money.