You can enroll in Medicare starting three months prior to the month of your 65th birthday and extending for three months after the month of your birthday.
(If your birthday is on the first of the month, you can enroll beginning four months prior to the month of your 65th birthday but only two months after the month of your birthday).
Missing your Medicare enrollment can have serious consequences. If you do not sign up for Part B and do not have health coverage after becoming eligible for Part B, you will pay a penalty if you ever do get Part B. The penalty lasts as long as you have Part B.
Also, signing up for Medicare supplement insurance, Part D, and Medicare Advantage plans is impacted by when you enroll in Medicare. After enrolling in Medicare, be sure to sign up for any other coverage you need.