I have eFiled my return already, but I have not submitted a form 1098-T I have. Will that affect me in some way? I am a resident alien.

what do you mean "not submitted" ?   IRS gets a copy of the form anyways.

Or did you mean you did not enter into TurboTax?

That's it, I have not entered it into TurboTax... What can I do?

if IRS has already accepted your return for processing, you should hold still till your refund is issued ( or you confirm that the processing is finished  -- about four weeks or less ). Thereafter you can amend your return to show the effects of 1098-T and mail the 1040-X to the IRS.  Which country are you from?  When did you enter this country and with what visa? what is your visa now ?

Yes, I got an email from TurboTax saying my tax return was accepted by the IRS. I am from Peru, and I came here on an F1 visa back in 2012. Thank you so much for your answer! Can I amend my return through TurboTax too?

Yes , you should be able to use TurboTax to amend your return.  Bien venidos a EEUA