Did you do dual enrollment? At a community college? If so, you might want to transfer to your state university for a cost-effective way to finish, and then look at Harvard for grad school. Often there at automatic transfers to a state U. (check your state) with benefits like early registration for community college transfers.
If you come from a family with income under $150k, you would pay 10%, and if under $65k, you would go to Harvard for free, so that is also a good financial option if it fits, but you would do the whole 4 years, not two, since your courses during high school would not count.
I wonder why you want to be a cardiac surgeon. That is a very specific career goal for someone your age. Make sure to plan for possible changes in your goals as time goes on. Many want medical school but many also change their minds 
People on this forum often advise against schools like Harvard for undergrad if you really do want medical school, because you will no doubt have a higher GPA elsewhere and apparently med schools care a lot about GPA in admissions.