Can you be more specific about your work experience? Full-time or internship? How long?
It seems like you have very little actual work experience to be considering a top tier MBA, which isn't a knock against you personally, it's just the timing of life which makes for an uphill climb in the admissions process. Some schools will recruit people in your situation, but even many of those schools will tell you that it's probably wise for you to work more before applying. Other schools are aware of situations like yours and offer a different path. Duke, for example, offers a 1Y MMS degree designed for less experienced candidates. The MMS will help you get into business, you work a few years, and then you come back and apply for the MBA.
If you are set on a MBA, I think you'll have to decide between getting one at a school outside the Top 15, or following a different path for a bit, and coming back with enough firepower to land inside the Top 15. Depending on the work experience you can get, Top 7 would sound possible as well.
You have all the rest of the pieces. Interesting story, great undergrad, entrepreneurial goals!