This is just a thought so if other posters think I’m wrong feel free to correct me BUT:
If it was me, I would look at the schools, and try to see if they had information about the test scores/GPAs that are required for admittance into the school of engineering (or wherever compsci is located) vs arts/sciences (or wherever biochem is located). Then, given my indecisiveness, I might apply to whichever one is more competitive because then it would probably be easier to switch into the less competitive one.