After you file

There will be no penalties or interest for this situation however you can choose to amend now and get ahead of the IRS notice  or wait for it to come in the mail and address it then to refute the taxes/penalties/interest that will be on that notice.  You will have to address it eventually so choose when/how you will handle this return error. Personally I would do it now so it is not hanging over your head for that IRS notice to come.