It's my understanding that most med schools will want to see some type of health care related exposure, whether it be volunteering or paid work. You should check with the admissions office for the schools you are interested in, but several friends of mine who applied to med school had CNA or similar experience at some point in their background. Aside from helping you as a candidate, it would also help you as a future physician to have hands-on experience with patients from the bottom up, so to speak, to see them as real people. Some of the best physicians I know had nursing experience before med school. I would suggest, though, that you not tell your fellow CNAs that you are doing this to build a pre-med resume -- while some may be supportive, others may hold it against you.
ETA: Llg (above post) is correct in that we are a nursing forum, not a doc forum. We cannot give you med school advice any more than you would go to a pre-med forum to ask questions about getting into nursing school. My advice was from the viewpoint of someone who explored med school before deciding on nursing school; take it for what it may be worth.
Last edit by sueall on Jul 9, '13