Age has no bearing on whether your income is taxable.
If your total income is less than the standard deduction for your filing status you will not have taxable income.
Standard deductions for 2019
Single - $12,200 add $1,650 if age 65 or older
Married Filing Separately - $12,200 add $1,300 if age 65 or older
Married Filing Jointly - $24,400 add $1,300 for each spouse age 65 or older
Head of Household - $18,350 add $1,650 if age 65 or older
If you are also collecting Social Security benefits -
Up to 85% of Social Security Retirement/Disability/Survivors benefits becomes taxable when all your other income plus 1/2 your social security reaches:
- Married Filing Jointly - $32,000
- Single or Head of Household - $25,000
- Married Filing Separately - 0