You can't get a monetary benefit (reduction of taxes) from paying student loan interest unless you actually owe tax.
You are required to file a tax return if you have other income non from social security (like a pension or 401k withdrawals). Whether or not you owe tax, and might benefit from the student loan interest deduction, depends on all your income and other circumstances.
To determine if you must file, see this IRS page.
https://www.irs.gov/help/ita/do-i-need-to-file-a-tax-return
