<p>..........in terms of starting to take the required prerequisite classes? Sophomore year? Junior year?</p>
<p>It’s never “too late”. You can take an extra year or two to complete your degree, or you can graduate and take the pre-reqs afterward. Plenty of people apply to medical school long after they’ve graduated, after having worked in another field for a few years, after having taken a few years off, after changing their mind about their current career and deciding they’d like to go into medicine, etc.</p>
<p>Generally, you should plan on pre-reqs taking 2 years (or ~4 semesters), if that helps at all, given the time frame in which you’d like to apply.</p>