Dear Carrie: I'm turning 65 next year. I'm still working and plan to continue for at least a couple more years, so I won't yet file for Social Security. I do, however, want to get Medicare. What do I need to do to make sure I get the right coverage? -- A Reader

Dear Reader: According to recent Gallup statistics, 34 percent of Americans now say they will retire after age 65, so your question is certainly relevant. It's especially relevant because, while enrollment in Medicare is automatic if you've already filed for Social Security, when you're not receiving Social Security, enrollment is in your hands. To make sure you get your Medicare benefits sooner rather than later -- and don't get hit with a penalty for late enrollment -- you need to be aware of certain rules and timelines.

HOW AND WHEN TO ENROLL

If you aren't getting Social Security benefits at age 65, you're still eligible for full Medicare benefits. This includes the premium-free Part A (hospitalization), as well as Part B (doctors' visits and outpatient care) and Part D (prescription drugs) for each of which you will pay a premium. But it's up to you to contact Social Security to sign up, and you must do this within what's called your Initial Enrollment Period. Generally, this period extends from three months before the month you turn 65 until three months after the month you turn 65 -- a seven-month period in total.

If you miss this Initial Enrollment Period, you may have to wait until what's called the General Enrollment Period, which runs from Jan. 1 through March 31 each year. There are a couple of drawbacks to waiting. First, your benefits won't start until July 1 of the year in which you enroll. And secondly, you may have to pay a penalty for late enrollment.

If you want your Medicare benefits to start right away when you turn 65, you have to sign up during the three months before your birthday. Otherwise, your benefits could be delayed by one to three months.

EXCEPTIONS IF YOU'RE COVERED BY YOUR EMPLOYER'S PLAN

Since you plan to keep working, you may still have medical insurance through your employer. If this is the case, the timing is a little looser. When you're covered by a group plan -- either through your own employer or your spouse's -- you can choose to enroll in Part B at any time while you're still covered by that plan. When your employment or group coverage ends, you then have eight months in which to sign up. Since its free, you could still sign up for Part A during your Initial Enrollment Period, but you could delay signing up for Part B (and delay paying the premium).

Another alternative is to enroll in both Parts A and B at the same time and consider Medicare as your secondary insurance, which would pay for any services not covered by your employer's health plan. There are federal regulations that come into play here if your company has fewer than 20 employees, so it's probably a good idea to talk to your employer's human resources department or plan administrator before making your decision.

WHAT YOU CAN EXPECT TO PAY FOR PREMIUMS

Premiums for new Medicare participants currently vary widely -- from $110.50 to $353.60 per month, depending on your income (the current ranges are $85,000 or less to above $214,000 for single filers; $170,000 or less to above $428,000 for married filing jointly). Therefore, your decision whether or not to enroll in Part B while you're still working might depend on how much money you're making. Also, note that your premium is based on your income two years prior to when you enroll. If you're making less now, it's possible that your most recent tax year can be used to calculate your premium if you meet certain criteria.

It's easy to get bogged down in all the details, but the most important thing is to stay on top of the dates and contact the Social Security Administration within your Initial Enrollment Period. In the meantime, there's plenty of very good information on the Medicare website (www.medicare.gov), including publications you can download and print for future reference. With the facts in hand, you can relax and enjoy some of the very real perks that come with getting older.