You don't need your 2019 AGI for anything now. You will need your 2020 AGI to efile 2021.
Do you still need to file 2020? You have to print and mail 2020 now so you don't need the AGI. And if you did not file 2020 by August 2021 then you should enter 0 for the AGI to efile 2021 now.
