are you a student and a dependent?   if so, 1098T goes on your parents' tax return

I may be that your parents claimed the tuition credit , in past years, meaning you cannot file amended returns and claim it for yourself.

Furthermore, a student, under age 24, is only eligible for the refundable portion of the American Opportunity Credit if he supports himself by working. You cannot be supporting yourself on parental support, 529 plans or student loans & grants. You must have actually paid tuition, not had it paid by scholarships & grants.  It is usually best if the parent claims that credit.  
You cannot claim a credit if you are, or can be, claimed as a dependent by someone else.

Why is it usually best if a parent claims the credit? I'm not sure if I am a dependent (finding that out now), but I am a student.

Update: my parents don't claim me as a dependent.

In that case you can claim the credit and if the same situation applies to previous returns you can go back 3 years and amend them.  Note that you must check the box that says someone can claim you but that they did not, if that I your situation. In that case you will not get any refundable credit.

Don't claim you is not the same as they could claim you ... if you are an eligible dependent you cannot claim yourself even if they do not claim you.  And to get the AOC you must support yourself with earned income not loans or scholarships.  Seek professional guidance if needed so you get this done correctly.

Thank you for the replies. Can I amend past years returns even after I've graduated?

Yes, as long as you were a student in the year you are amending for.

Be advised here are two education credits: American Opportunity credit (AOC) and Lifetime Learning Credit (LLC).  The AOC is more generous but is not available to grad students. The earned income rule for the refundable portion of the AOC is applicable, for students under 24, even if you cannot be claimed as a dependent.

Select a tax year for specific amending instructions.

Keep in mind: You have 3 years from the date you filed your return (or 2 years after you paid the tax due, whichever is later) to file an amended return, which means you don't have to get it done by the April 15 filing deadline.

·         2018

·         2017

·         2016

·         2015