Below is information on how to find your 2017 return to obtain your AGI amount:
https://ttlc.intuit.com/replies/3301618
Note that if you do not have
access to your prior year return, you can request a free online transcript of
your 2017 tax return from the IRS. The transcript will include your 2017
AGI amount on it. Use this link: IRS Get Transcript
