First of all, you have to have the proper filing status – which in this case means that you can be of any filing status except for if you are married and still filing your taxes separately. There is no explanation given as to why this particular status is exempt, however, this is still important to take note of before you waste your time trying to fill out a deduction that you cannot claim.
The other thing that is necessary in order for you to claim that deduction is that you cannot have another person claim you as a dependent or a tax exemption on their own tax forms. For most people who have already graduated from college and are trying to pay off their student loans, this should not be too much trouble. However, you should still make sure that nobody in your life is still claiming you as a tax deduction.