Can I avoid fraud charges on past tax returns?

[btape]

I'm sure that I did not pay the proper amount of taxes in my last two returns. I only reported the amount I withdrew to my bank accounts, and not what I withdrew with my neteller atm card. I know I was supposed to pay taxes on everything, but I was 18 at the time and stupidly decided not to. I would assume that leaving it be could constitute fraud if I were ever audited. Now, if I went back and found out the correct amounts and filed ammended returns, could I face non-monetary penalties? I'm not worried about having to pay interest or anything like that, and I just want to have a clean tax record should I get audited in the future.

So I guess my question is, if I take the initiative and correct my tax returns before getting caught, can I avoid any criminal penalties or anything else more severe than fines even though I committed fraud in the past?