Forget about the extension, it's not important now. What other income do you have besides Social Security? Here a few links
Do you need to file a return?
https://ttlc.intuit.com/community/filing-and-paying-taxes/help/do-i-need-to-file-a-federal-return-th...
IRS Do I need to file?
Do I Need to File a Tax Return? | Internal Revenue Service
See IRS pub 501 for filing requirements
https://www.irs.gov/pub/irs-pdf/p501.pdf
