My freshman year, I did almost nothing medically related, except for going to one or two meetings of the pre-med society, something I haven't done since that year. I studied pretty hard, and got my best semester GPAs yet. I think admissions committees are more concerned with your later college years, and your overall stats, as well as a positive trend in grades. So don't worry too much about your first year, have fun and get a good GPA. The transition from high school to college takes some adjustment, so I wouldn't try to overdo it by doing a ton of volunteering, just find out what organizations can be outlets for that type of work, you'll have plenty of time to volunteer in later years. I don't think they'll let freshmen do research here so that wasn't even an option, and I wouldn't suggest doing that year 1 if it is at your school. Maybe I'm just lazy, but I say save that stuff for the other 3 years, it will be closer to the time you write your personal statement and answer interview questions.