To get the additional standard deduction you have to be 65 or older on January 1 following the end of the tax year. To get the additional standard deduction on your 2017 tax return, which you are filing now, you have to be 65 on or before January 1, 2018. (Your date of birth has to be before January 2, 1953.) To get the additional standard deduction on your 2018 tax return, which you will file in 2019, you have to be 65 on or before January 1, 2019. (Your date of birth has to be before January 2, 1954.)
