Yes, it is possible to prepare your own 2017 Tax Return using TurboTax. You can purchase and download the software for 2017 to prepare the return and then mail it to the IRS. Only your current year Tax Return can be done with TurboTax Online.
You have until 4/15/21 to file your 2017 Tax Return or you will not be able to claim any refund that you are due for that year.
Here is link to previous years product options: TurboTax Previous Years Products.