Hi, I married my fiance Jan of this year. When I filed for tax this month, I filed as married filing jointly. My wife is a student and does not have income. Now I found out that if I married in Jan, I can't file as married because the tax year only includes up to Dec of last year.

Is it worth it to amend this honest mistake? If I just leave it as it is, will I get penalty fee?

Thank you so much for your input and advice!