You are auto-enrolled into the Federal Employees Group Life Insurance (FEGLI) program as soon as you make a career. Ensure that you want these benefits or need to make any changes as open season for this is not yearly. There are optional coverages that you can enroll in that are priced based on your age. The basic coverage that you are auto-enrolled in is not impacted by your age. The Postal Service pays one-third of the basic coverage but not any toward any optional changes you might make.
Head over to the OPM website, or see attached brochure.