Hey, check with the issuer. If you really do have a 2017 W-2, then that "has" to be reported on a 2017 tax return. You can't report a 2017 W-2 on a tax return for any other year. I strongly suspect your employer may have issued you the wrong year form for 2018. So check with your employer to confirm the validity of those W-2's for your 2018 taxes. If you report 2017 income on a 2018 return, you will have major issues with the IRS that can (and probably will) delay any refund you may be due.
