First things first... if you actually plan to pursue your career the way you planned it then be prepared for a long haul... at least 7 years before you finally get that goal. For Medical you can opt for any of the prestigious exams like AIIMS, DPMT. AIPMT etc. You can keep preparing for IAS even during your degree course. But certainly not at the cost of you academics. Towards the last year of your degree you can start preparing for UPSC a bit more seriously, but you should still keep a buffer of at least 2 years for preparation after you finish with your degree. For rest of the inputs kindly go through highly informing articles in this website.