Page 3 of this pdf lists a waiver for those 62 or older that retired during the year.
https://tax.iowa.gov/sites/files/idr/forms1/2017IA2210%2845007%29.pdf
The next link is the actual waiver Form for the state of Iowa.
If not sure, I would file it, you might get the penalty waived.
https://tax.iowa.gov/sites/files/idr/forms1/Penalty%20Waiver%20Request%20%2878-629%29.pdf
