Simple answer: yes. Sinve you haven't completed the degree requirements, you are not considered to have completed 4 years.
You say " I haven't claimed the credit four times". Any credits, on your education, claimed by your parents also count toward the four times.
Be advised that a full time unmarried 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 usually 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.
