Trying to break into IB, High schooler who needs help.

Throughout high school I always thought I wanted to become a doctor. I volunteered in medical clubs, did research, and more and I thought I was in love with research and that was the way to go. As I progressed, I found myself stuck in the medical field. I found myself drawn to research that cut costs in the medical field, specifically redesigning pharmaceutical drugs to have a smaller production cost and creating products that cut costs in hospital/restaurant applications but I was rejected by multiple science fairs due to the nature of my research not being "science related enough??" I was recommended by someone to enter a business competition and I actually placed nationally. As I delved into business, I found that I loved the entire networking aspect, meeting new people and exchanging ideas and through taking finance courses at my local community college I realized that I might like finance more than I did biology. However, going to a super competitive high school and having issues with diagnosed ADHD (I promise I am not self diagnosing, I have been sent to the school counselor multiple times to talk about this but my parents wont let me take any medication), made it really hard to get good grades (I took hard classes) and so I am graduating with about a 3.65 and a 1520 on the SAT making it impossible to get into any business targets. Furthermore, all my essays are written about biology and since all my ecs are biology related and since I am halfway through with college applications, I do not know how I can enter the IB field at this point. I applied to penn state and IU kelley into finance but I mostly applied as a biology major since that is my highest chance of admission into college. How do I redirect myself in college into getting into investment banking entering freshman year as a biology major which will probably also kill my gpa. I am really passionate about entering finance but I am afraid that my path in high school might not make that possible. I am sorry if I am coming off as ignorant but I genuinely need guidance as I don't know what are my options at this point and if I should just give up on finance completely and stick to biology.