Hi Yumi,
Congrats to you for being so proactive about taking supplementary coursework. I find that to be the thorn in the side of many of my clients who wait until the last minute to think about this.
When I applied to HBS myself, I was conditionally accepted (a rare, if not nonexistent anymore, occurrence). I had to take supplementary coursework to prove I was REALLY ready for the Harvard classroom. Additionally, I have recommended that some of my clients who have low GPAs (under 3.6) or little quant experience to take supplementary coursework as well. I recommend you take the following courses if you have not yet taken them and earn a B+ or better in them (in order of importance):
1) Accounting
2) Finance
3) Statistics
4) Microeconomics
5) Calculus
You are right that it is completely fine to take them at a community college. Don't pay a lot more money to take these courses at a fancy institution unless you really just want to do that.
I took Corporate Finance through BYU Independent Study and recommend them if you're interested in online learning. However, a community college is just fine as well.
Good luck with your process!
Kaneisha
Harvard Business School MBA 2010, Harvard Kennedy School MPA 2010
Founder, The Art of Applying
Admissions Consulting for MBA, MPP, Joint Degrees, and Fellowships
https://theartofapplying.com
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