First of all, congratulations with your first salary, but there are some things that people never tell you about adulthood. Enrollment into Medicare is surely not one of those things, and that is good news since the government will never think that you really need Medicare at such age. You are certainly below the age of sixty-five years, thus, considered by them as a young man who cannot benefit from Medicare programs.
However, there are some positive news: you do not have to enroll into Medicare program at the moment. The age of eligibility usually starts at the age of sixty-five, and it seems rather impossible to think about it in your little cubicle right now. If you already have your job, you are expected to enroll into an employer-sponsored group health plan rather than Medicare.
There are some special conditions that will make you eligible for Medicare program, but they apply only to very rare cases. Usually, when you finish college, you will not have anything to do with Medicare. Thus, forget about any information concerning Medicare during at least forty years and think about your 401k instead. Have fun while you are still young and can walk! 😎