Taxes

I am in the United States. I am working here. Ergo I should be paying taxes. I did file an extension, but that is about to expire. And I’m discovering how just how complicated it is.
One thing that has come up is that apparently I should have been paying US taxes for my entire life. My company was willing to pay for me to do my US taxes for the first year, but the firm refused to do that unless I completed all of my back-taxes.
Through my wife we found an accountant that would be able to help me. She lives in Kimberley, B.C. which is a ski resort town. She seems very knowledgeable and has been helpful. Thankfully the U.S. is forgiving; I only have to do the last three years of tax returns. I suppose I could have just had her do them all EXCEPT for the last one and had my company do those. But it feels safer to just have one party do all of them.
In any case, we went over the returns today and it oddly looks like I will actually get money back. Score! Maybe the U.S. should not have been so insistent I go through this exercise.