I hope you are not using TurboTax as a paid tax preparer because that would be a violation of the licensing agreement. You don't need the 2016 AGI to file a 2017 return since it cannot be e-filed anyway and the AGI is only needed for e-filed returns. The 2017 return will also not not rejected because mailed returns are not rejected and you can only file 2017 by mail.
