There are many, many people who do not understand how the tax system works. It’s not necessarily a character flaw.
In my years of poking around in others’ business as part of my job in finaid, I have found that folks who earn very little often do not understand taxes … and the folks they pay to assist them in filing are often either not asking the right questions or providing bad advice. One of the biggest issues I had was untaxed income. Students and parents were honest and put it on the FAFSA … but they did not understand that it doesn’t take much untaxed income to require filing a tax return. I had to give the dreaded ultimatum: File for the prior year or no aid. It is not easy to be the heavy, but as soon as I saw untaxed income greater than the filing requirement, I was bound by regulations to be the hard-a**.
So, OP … I will assume everything will be by the books for 2015 (the year in question for 16-17 FAFSA). You may end up with a 0 EFC simply due to your parent’s low income. In that case, you won’t need to tell anyone anything about your situation … 0 is as low as it goes. If the EFC is greater than 0, you can request a professional judgment review of your situation. No PJ’s will be done this early, though.