<p>Did you already pay the deposit to CMU? If you already paid it, you are expected to withdraw from there if you now join Georgia Tech.</p>
<p>I am not sure about where CMU or Columbia stand for BME since I cant find any rankings for them. However, Georgia Tech is number 3 in the list after Johns Hopkins and Duke. For overall college rankings, Columbia is 4, CMU is 23 and Georgia Tech is 35. </p>
<p>So it depends on whether you want to worry about college rankings or department rankings.</p>