Yes, you have three years to amend.
if your marital status on 12-31-16 was married, you are allowed to file as married Filing jointly for 2016 no matter how briefly you were married.
In fact, if your marital status on 12-31-16 was married, you are not allowed to file Single or Head of household (HoH)*. Your only choices are married Filing jointly (MFJ) or married Filing separately (MFS).
*There is an exception for HoH, if you have a dependent and did not live with your spouse at any time Jul 1- Dec 31.
