The IRS Q and A mentions you can use it in grad school so long as you have not completed four years of post high school education and have not claimed it four times (https://www.irs.gov/credits-deductions/individuals/education-credits-questions-and-answers) - see Q9. Although I'm still hazy on whether I had completed four years of post secondary education if I graduated with a bachelor's in 3 years post high school because of AP and language credit I tested out of.
If I completed my bachelor's degree in 3 academic years (2013-16) could I have claimed the American Opportunity Credit for 2018 during my first year of grad school? The AOTC was claimed by/for me in 2014, 2015, and 2016, so if I have one more year of eligibility I would like to amend my 2018 return to claim it as that would significantly increase my refund. And are they counting academic years or tax year for the "four years" as I was in college during 2013, 2014, 2015, and 2016, but that is only 3 academic years (again I only claimed it 3x, my parents did not claim it for me in 2013).
Sorry for beating the dead horse, but would make a big difference if I can claim it for the first year of grad school.
