Yes, you should Amend the tax return and you would go to Personal Information section and Edit the new born.
Show the child as living with you the entire year (year of birth).
Once the return has been filed it cannot be stopped (unless you get extremely lucky and IRS would reject it for some reason).
So you have to wait for the return to be processed and you get your refund.
Then approx. March 7th you can sign back into TurboTax and do the Amended return.
