I am eligible for the Earned income credit but the system is not allowing me to add it. I have earned income and none of the disqualifying options apply to me.

The program will complete the EITC automatically if you qualify for the credit.  Read the rules here to make sure you qualify ...  https://www.irs.gov/credits-deductions/individuals/earned-income-tax-credit/earned-income-and-earned-income-tax-credit-eitc-tables

If you are eligible for EIC the software adds it to your return automatically, so I suspect you might be mistaken about your eligibility.   

Please use the IRS eitc assistant to see what it says:

https://www.irs.gov/credits-deductions/individuals/earned-income-tax-credit/use-the-eitc-assistant