You are not required to file a federal return since your income is under the $13,600 filing threshold for 2018. Please view the TurboTax FAq below for more information.
https://ttlc.intuit.com/replies/3302274
You are also not required to file a South Carolina state return since you are over the age of 65 and your income is under the federal filing requirement. Please view the South Carolina link below for more information.
https://dor.sc.gov/tax/individual-income/faq