I guess if the process was strictly comparative and they made the decisions about who to accept all at the same time you would want to be the last to interview because you would be at the forefront of their memory being the last to leave an imprssion before decision time....HOWEVER....
medical schools DO NOT fill their classes this way. The admissions process works on the now famous "rolling admission basis" so as qualified applicants are interviewed and impress the adcoms, they will be offered acceptances and hence the filling process begins.....naturallly then in this type of arrangement being the first to interview kind of assures that there is still PLENTY of seats left, and additionally you are being compared up against fewer applicants than those who apply later in the process.
so assuming you are a good candidate for the school (which you must be if you have been offered an interview), then being the "first in line" when the doors open is generally considered an advantage.
Good Luck!
