Did you just use the current online software to prepare a 2016 return and e-file it? If so, then yes, you really messed up. The current online software is ONLY for preparing and filing a 2017 tax return. And now if you e-filed it, it is going to sit on a server until January 29 at the earliest, before you even hear if it was accepted or rejected. You cannot do one thing about it now. You should not try to change it in any way. WAIT until late January. If the return is rejected you will be able to clear it and start over using the software for your 2017 tax return. If the IRS accepts that return with your 2016 information on it, you are going to have to amend the return in order to put your 2017 information on it--this is a process that requires a form called a 1040X. The Form 1040X usually becomes available in late February. It has to be printed, signed and mailed, and then it takes the IRS about 3 to 4 months to process it.
Meanwhile, you can still prepare your 2016 tax return if you use the correct software to do it. You have to purchase desktop software, and then print, sign and mail your 2016 return. It cannot be e-filed.
To file a return for a prior tax year
Only a 2017 return can be prepared online and e-filed.
If you need to prepare a return for 2014, 2015, or 2016 you can purchase and download desktop software to do it, then print, sign, and mail the return(s)
Remember to prepare your state return as well—if you live in a state that has a state income tax.
When you mail a tax return, you need to attach any documents showing tax withheld, such as your W-2’s or any 1099’s. Use a mailing service that will track it, such as UPS or certified mail so you will know the IRS received the return.