Unfortunately, since the purchase date of the vehicle was in 2017, you would need to amend your 2017 return in order to claim the credit.
Go here and get instructions for amending that return. Amended returns have to be printed and mailed in and take up to 16 weeks to be processed.
One important note: Before you start the process of amending the return in TurboTax, be sure you have printed a copy of your original return or have saved a PDF copy to your computer.
