You can all the IRS at 18008291040 to request your AGI, You can also follow the link below to the IRS website that gives some additional ways to retrieve your AGI if you are unable to log into turbo tax.
https://www.irs.gov/individuals/electronic-filing-pin-request
If you have forgotten your turbo tax username or password you can follow these steps to recover your account, you can then log in and find your AGI on your previous years tax return
https://ttlc.intuit.com/questions/1901535-forgot-your-turbotax-online-user-id-or-password
Here is another link to an article on turbo tax that tells you a few other ways you can find your AGI
To access your current or prior year online tax returns sign onto the TurboTax website with the userID you used to create the account - https://myturbotax.intuit.com/
Scroll down to the bottom of the screen and on the section Your tax returns & documents click on Show. Click on the Yearand Click on View adjusted gross income (AGI)
You can also get free transcripts of your federal return from the IRS - http://www.irs.gov/Individuals/Get-Transcript