Google AAMC Table 25. That will show you how many premeds including traditional and non-traditional apply in a 2 year period and how many actually get admitted with tables stratified by race. There are also other tables showing similar stats by major, by state, etc. When all is said and done, of those who get far enough along to apply, the proportion who get admitted to at least one medical school is about 45%. Of course, many fall by the wayside and change their career plans after freshman year, after organic chemistry, after taking the MCAT, after getting arrested, etc, etc before they even apply for admission.
To avoid being another statistics:
Work hard and keep your grades up
Keep your nose clean; don't cheat
Find time for worthwhile and fun activities
Get a taste of research
Give some of your time in service to others
Arrange for an employment or volunteer experience in a setting with patients
If you are at the start now, at the end of your second year, find a schedule for preparing for the MCAT and prepare to take the MCAT in Spring of your Junior year. If you are a non-trad, plan on the MCAT at the point where you are taking the last of your pre-reqs.