Not quite sure what you are trying to do. If you filed a tax return by mail and a check was mailed to you, you do not need your 2018 AGI any more. That was only needed to e-file a 2019 return. As for changing your address, you can change your address with the IRS:
https://www.irs.gov/forms-pubs/about-form-8822
Be sure you also filled out a change of address form for the Post Office so mail will be forwarded to your new address.
The IRS can look at your 2018 or 2019 return to issue a stimulus check. If they do not have a 2018 return then you may be waiting for them to finish processing 2019 before they will be able to use it to issue your stimulus check.
If you used the non-filer site, you will not be able to e-file a 2019 return after using the non-filer site.
TurboTax has no control over your stimulus check, nor can TT track it for you or tell you when the IRS will issue it. Refer to the sites linked below:
You can call the IRS hotline at 1-800-919-9835 to get updates on your stimulus payment.
https://www.irs.gov/coronavirus/economic-impact-payment-information-center#nonfilertool
https://www.irs.gov/coronavirus/get-my-payment-frequently-asked-questions
https://ttlc.intuit.com/community/tax-topics/help/how-will-the-stimulus-package-impact-me/00/1393859
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
