But the site also states most error free e-filed returns could take 21days as well
@gdstyson you are correct, and it may be they just haven't updated that section of the website yet. But when you go to the page to put in your social and expected refund amount, they have the 2018 Updates for returns there; which state the 90 days. You can see that here <a rel="nofollow" target="_blank" href="https://gtc.dor.ga.gov/_/">https://gtc.dor.ga.gov/_/</a> which should take you to their "Where's My Refund" page
If you are processing, then you are fine. But know that it could take up to 90 days to complete processing, per GA's website.