My freshman year in high school I was not very serious about school and finished with a weighted GPA of 3.1. I started getting serious about school late freshman year and was able to take tests to allow me to take AP classes this year and I now have a weighted GPA of 4.8. I also took the PSAT and scored in 97th percentile for sophomores. My dream scenario is to get my Bachelors Degree at Harvard and then attend law school there but due to my poor freshman grades I do not believe this is likely. My second choice for college would be the University of South Carolina considering I live very close to the school but I would not want to attend law school there due to lack of prestige. I would like to know if my best shot at getting in to Harvard Law would be to try to get my bachelors from Harvard. I know the acceptance rate is incredibly low which is what you would expect with such a prestigious school so I want to know everything I can do to maximize my chances of getting in to Harvard law after likely receiving my bachelors from U of SC. I know I am only a sophomore in high school and I am thinking way ahead but I just want to be prepared. I am just asking for any advice from perhaps someone who has attended or attends Harvard.
You basically said this yourself: it is way too early to be thinking about this. Your career goals may change. Most young people know about medicine and law, but there are many other options out there that you will learn about as you go along. You don’t need to think about law school for at least 6 years. Try to live more in the present, and work hard for the right reasons (not to get in to a particular school, but to have a good foundation for wherever you do go.) Explore your interests and develop friendships and work hard and things will work out. Volunteering outside of school, or working, can be clarifying as well.
Sometimes overplanning actually interferes with opportunities, because by planning prematurely you are not as open to opportunities that appear on your path 
In any case you don’t need to go to H to get into HLS. Recent figures published by HLS list 172 different undergraduate schools represented in the 1L class alone. And everything @compmom said is right.