I'd recommend using the IRS webpage linked below to view a transcript (abbreviated version) of your 2017 return. That transcript will include your 2017 AGI, so you can proceed with e-filing.
https://www.irs.gov/individuals/get-transcript
Then, to correct your 2017 AGI in TurboTax, see the info below.
https://ttlc.intuit.com/replies/4168567
*** I am NOT a tax expert. I am a seasoned TurboTax user, and volunteer to provide assistance to TT users. Nothing I post is to be considered TAX ADVICE; I bear no legal liability for responses.***
