Rather than a negative factor, your involvement with international tax can be a plus, since it is both distinctive and highly relevant for complex global transactions. However, don’t assume the adcoms’ appreciation of this fact – use your application and essays to portray how vital this area is; make them see it with your eyes. If you do it right, you will both enlighten and impress them.
Other points – since you’re aiming for 2015, if you can prep for the GMAT, you might consider trying to add that test. The programs do accept the GRE and will note your score, but generally they are still more comfortable with the GMAT and feel it’s a better tool for their assessment.
Your school list looks on target at this point; there are certainly other possibilities, and I suggest using this year to continue exploring. One program that's often overlooked for entrepreneurship is Chicago Booth; its Polsky Center for Entrepreneurship is a great resource.
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