Focus on getting good grades in a rigorous curriculum. You might consider retaking the SAT because it is on the low side for these uber competitive programs.
It’s good to have dreams and goals, but IMO it is difficult to know you want to become a physician in the absence of ever having worked with patients. Most students who end up becoming physicians did not do so via a BS/MD program.
When researching BS/MD programs make sure to understand the requirements (GPA to remain in program, ease of getting patient facing experience, MCAT required or not, etc.). For example, there is quite a bit of variance in required GPA, and some are really high (e.g., WUSTL).
Lastly, make sure to have plans B and C, as most undergrads who go in as pre-meds do not end up going to med school.
Good luck.