<human>: Condense the text into a few key points

Not really an overly complicated question, but I really do like this girl and I don't want to screw it up.  Basically, I am a medical student who just spent 6 weeks working with another medical student (the girl) on a rotation.  After about a week, I knew I wanted to ask her out, but I decided that I should probably wait until after our rotation so as to not make the work situation potentially awkward.  So we ended up becoming good friends during the rotation.  Not like super duper close friends or anything, but good friends nonetheless.

From the way that we talk to each other (it involves a good amount of light-hearted flirting), I am fairly certain that I haven't been friend-zoned.  But that is beside the point, anyway.

The issue is all about timing.  Since the rotation I am speaking of is the last rotation of our third year of medical school, we now get a little bit over 2 weeks off to study for this huge exam (USMLE Step 2 CK, if anyone is interested).  I really want to ask her out, but I know that the potential date won't be for at least 2-3 weeks (once the exam is over with).

So the question is, should I call her now and try to get the date for 3 weeks later, or should I wait a couple of weeks and call her closer to when the actual date would happen?  I really want to just call her now, but I feel like 3 weeks of minimal conversation in between would be really awkward.  Any advice?
<bot>: I want to ask a girl out for a date that would happen 3 weeks later in advance.  Should I do it now, or wait until closer to then?