Q. I graduated college in 3 years and I'm in my 4th year of higher education, but first year of graduate school. Do I qualify for the American Opportunity Credit?
A. No. Graduating means you have completed first 4 years of postsecondary education. See wording from Pub 970 below
You said: "I've never received this credit before and this is my first time filing as an individual and not a dependent".
The times that the parent claimed the AOTC, on your education, counts against your 4 times. 3 academic years usually equals 4 calendar years. So, they may have already claimed it the maximum 4 times.
[EDIT] As noted by @RayW7 , if you attended both undergrad and graduate school, in 2020, you can still claim the AOTC for 2020, because you had not completed your 4 years before the beginning of 2020.
From IRS Publication 970
As of the beginning of 2020, the student had not completed the first 4 years of postsecondary education
(generally, the freshman through senior years of college), as determined by the eligible educational institution. For this purpose, don't include academic credit
awarded solely because of the student's performance
on proficiency examinations.
Completion of first 4 years. A student has completed
the first 4 years of postsecondary education if the institution at which the student is enrolled awards the student 4 years of academic credit at that institution for coursework completed by the student before 2020. This student generally wouldn't be an eligible student for purposes of the American opportunity credit.
Hadn't completed the first 4 years of postsecondary education (generally, the freshman through senior years) in an earlier tax year.
