Can IRS come after me for International bank accounts that were not declared in my taxes since I did not know that was a requirement?

I have been working on a visa in the United States in the years 2006-2007 and 2008, then left the country and came back in 2010 as a green card holder, starting to work again in the United States. In 2011 I lost my job and received unemployment for about 3 months. Finally in January 2012 ,I got again a stable job that I have still now. Summarizing I had to do tax declaration for the years 2006-2007-2008 (as a F-1/Optional Practical Training then J-1 visa holder) and for years 2010 and 2012 as a green card holder (did not have to do 2011 as my total income for that year was of about 4300 $). I just did my 2012 taxes with Human resources as usual. The guy told me to fill a form 8938 as I hold a non United States bank account with about $216000 in my home country (combination of the savings from my work before coming to the United States and a gift from my family). I filled it and I also put an estimate of the interest I made on this account in 2012 that is about $3100 (a mix of interest and capital gain coming from me playing a bit with the currency USD/EUR exchange). He also told me to fill a TD 90 F form by June 30 ( I will do). After all these things I made a personal research on these forms and I learnt that I should have declared this bank account in my homeland also in the past years (thing I did not do),the Human resource guy told me that is ok like that: Internal Revenue Services will appreciate my honesty in declaring it this year, but I don't buy it, I am fearing that IRS will come after me, triggered from the fact that I have a consistent amount of money abroad and they may ask me why I did not declare it before (I was not aware that was a requirement).