Turbotax may ask that question but that doesn’t mean it was all a deduction and surely not a credit. A deduction reduces your income so $50,000 income less $15,000 in mortgage interest and charitable contributions would be a taxable income of $35,000 (simplified for here). A $1,000 tax credit (say child tax credit) would reduce your tax owed dollar for dollar so if you owned $3,000 in taxes, you would owe $2,000 after a $1,000 credit.
The only option for your prior year is you misunderstood or did something wrong in which case it will come back to haunt you you. I expect it’s just a misunderstanding.