The 2018 AGI is on the 2018 Federal tax return you filed Form 1040 Line 7. To access your current or prior year tax returns sign onto the TurboTax website with the userID you used to create the account.
Scroll down to the bottom of the screen and on the section Your tax returns & documents click on Show. Click on the Year and Click on View adjusted gross income (AGI)
Please see the TurboTax FAQ below for additional information:
How do I find last year’s AGI?