Since no one can see your 2018 tax return or know your education status, that question cannot be answered. TurboTax does not receive any information from the IRS concerning our tax return or tax refund after the tax return was accepted by the IRS.
Did you claim the AOC in four tax years before tax year 2018? If you did then you were not eligible for the AOC in 2018.
IRS website for the AOC - https://www.irs.gov/credits-deductions/individuals/aotc
