Not sure what you think e-signing means. When you "sign" to e-file there is not a physical signature. You sign electronically by entering last year's AGI from line 8b of your 2019 Form 1040. If you did that, you signed. If you did not, then when the IRS starts to accept/reject returns on February 12, your return will be rejected and you can put that AGI in and try again.