Get your taxes done using TurboTax

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 filed a 2017 return but somebody claimed you as a dependent, enter the AGI from your 2017 return – not theirs.
• If you filed jointly last year but separately this year, enter the AGI from your joint 2017 return.
  • Same goes for recently-widowed or divorced taxpayers who filed jointly last year.
• If you're filing jointly this year but used Married Filing Separately last year, enter each spouse's AGI from their respective 2017 returns.
  • Same goes for newlywed couples.
• If you didn't file last year, enter 0.

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.

https://ttlc.intuit.com/replies/5578532