enter $0 since you never previously filed or if you previously file with another program, you will have to obtain that information.
Your 2017 AGI is exactly what is says – the AGI amount from your originally-filed 2017 tax return.
If you can not obtain your prior years tax return, you can always order a IRS transcript and file for an extension. Just make sure you pay estimated taxes by midnight tonigh so you won't be charged interest or penalties for not filing timely.
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