En español | You should probably enroll during the seven-month window known as your initial enrollment period. It begins three months before your 65th birthday, includes the month you turn age 65, and ends three months after the birthday month. For example, if you turn 65 on June 30, 2019, the enrollment window is open from March 1 to September 30.
If you miss this deadline, you may have to pay higher premiums for Medicare Part B, which covers doctor bills, outpatient fees and other medical expenses. However, some people who are still working at 65 and have health insurance through an employer group plan from current employment may be able to delay enrollment without this penalty.