I have been an international student since 2008 and haven't filed any taxes since then. I did my CPT in fall 2012 and earned less than $ 500 doing CPT last year. I graduated in 2012 and now I'm doing OPT in the same place that I did my CPT. I thought I did not need to file taxes since I earned so little, so didn't file taxes for 2012.

Can you tell me if I had to file taxes for 2012?
If yes, what forms should I use and how much would the penalty be?
Should I file 2012 taxes as soon as possible or next year when I file taxes for 2013?

Thank you so much for your help.

If your total income for 2012 was only $500, then your assumption was correct: you have no legal requirement to file a tax return.