You will use your 2012 returns to file a FAFSA for the 2013-2014 school year, so if you decide to start in January you'd use those. You'll use 2013 returns for the 2014-2015 school year. However, I am assuming that you want to go to school for more than one year so either way you'll need to file for 2013 at some point. I'm not sure I understand your concern. You can still file taxes for 2013, just submit the cash you earned as Misc. income. If your income is zero, you aren't going to be penalized, you will probably get more financial aid.