you will receive a package concerning courses & schedules prior to orientation. Chill. You’ll have plenty of time to work on First Year stuff over the summer.
Get back to studying for those APs.
But if you must be a gunner, now, look at each Department’s (math & Econ) web page for undergrad major requirements, and the Core requirements. It’s always good to take some Core classes early, rather than wait until Senior year.
Writing, English Lit, Foreign Lang (if you don’t AP or take the subject test), History?
http://www.bc.edu/sites/core/requirements.html
yes, transferring into CSOM is extremely difficult. But if you want that as a backup plan, then also take the CSOM Frosh courses. Portico is usually limited to CSOM students, but you might get into the others on a space-availble basis.
http://www.bc.edu/schools/csom/undergraduate/academics/core.html