Medical and health schools will want to see that you have tested your commitment to medicine, and that you're aware of what you're entering into. More importantly, you'll need to make sure for yourself that you've tested your commitment to the profession.
Since you're not yet a physician, it is (of course) impossible to practice as one, but there are plenty of other ways to get a better sense of the field. Many components of medical and health professions overlap with other experiences, such as empathizing with people when they're vulnerable, listening to their stories, and being of service. Volunteer or internship experiences allow you to assess how you feel while doing these tasks; shadowing (watching physicians work) will also give you some idea of whether you could see yourself enjoying the field. In addition, undergraduate and postgraduate research can further inform and enhance your preparation and decision to enter a medical or health profession.