You cannot enter a 2017 Form 1098-T on a 2018 tax return. If you want to enter the 1098-T then you will have to amend the 2017 tax return. An amended tax return can only be printed and mailed, it cannot be e-filed.
See this TurboTax support FAQ for amending a 2017 tax return - https://ttlc.intuit.com/questions/4252298-how-do-i-amend-a-2017-return-in-turbotax
