According to the American Association of Medical Colleges (AAMC), approximately 3.5% of this year's matriculants to medical school are entering at 30+ years old. I was in my early twenties when I started, and there was a definitive difference in maturity and composure between the "older" students in the class and the rest of us.
Traditionally, some medical schools have been reluctant to train older students, as they see their career longevity truncated compared to younger pupils', however, with increasing demand for physicians and burnout that may shorten younger doctors' careers anyway, some schools are now more open-minded.Here is a piece from the AAMC about folks who start medical school later.
