If you already get Social Security, you will be automatically be enrolled in Medicare Hospital Insurance (Medicare Part A) and Medical Insurance (Part B). You will receive information about
your benefits in the mail a couple weeks before you become eligible.  If you’re not on Social Security and not ready to get it yet, we suggest enrolling in Medicare 3 months before your 65th birthday. Use (link here) to see what you’re eligible for.
Because there is a premium associated with Medicare Part B, you may turn it down. However, doing so, can cause a delay in benefits when you do sign up, and can cause you to have to pay a late enrollment fee, or penalty. The premium can also go up for every 10-12 month period you were eligible but denied the insurance, but you may qualify for a special enrollment period.