So this suggests that you are within the top 20%, but not the top 10%. Previously, you mentioned that 50-70 out of the presumed 750 students in your class (1/4 of 3,000) go to “top 20 universities” every year, so being out of the top 10% makes it unlikely for you with respect to the “top 20 universities”.
However, Rutgers looks more likely for you based on the above.
It is complicated because each college can do things its own way, and because high school courses and grading are not consistent across the US, or even within a state.
Regarding declaring a major on frosh application, it depends on the college. It is best to indicate a major that is of your interest, because changing major into a more popular major later can be difficult or require another admission process.