It says based on what I've entered I am eligible to receive the American Opportunity Credit. I have claimed this before and I am in grad school and been in school 6 years

TurboTax has based its answer on the information you entered during the interview.

If you have completed the first four years of post-secondary education at the beginning of the tax year, then you are not eligible for the American Opportunity credit. 

Please revisit the Education section and check all your replies to the TurboTax interview.

To be eligible for AOTC, the student must:

• Be pursuing a degree or other recognized education credential
• Be enrolled at least half time for at least one academic period* beginning in the tax year
• Not have finished the first four years of higher education at the beginning of the tax year
• Not have claimed the AOTC or the former Hope credit for more than four tax years
• Not have a felony drug conviction at the end of the tax year

You should be eligible for the Lifetime Learning Credit, but it does not have a refundable feature.