<p>When you indicate your major on your application, you are already “choosing” the college you are applying to, because different majors are located in different colleges. Since some majors are more popular (engineering, maybe?) or are located in a more prestigious college (USC’s School of Cinematic Arts is the best of its kind in the nation), they will be more competitive to get into. Certain majors have supplemental requirements, which you can check here [USC</a> Admission - Additional Requirements](<a href=“http://www.usc.edu/admission/undergraduate/apply/additional_req.html]USC”>http://www.usc.edu/admission/undergraduate/apply/additional_req.html)</p>
<p>When evaluating your application, USC considers you for your first choice major - if you are rejected from that, then they consider you for your second choice. If you are rejected from all your choices, you are automatically considered as an “undeclared” major for the College of Letters, Arts and Sciences.</p>
<p>I’m not sure how difficult it is to switch majors/colleges once you have been admitted, but it’s definitely achievable. Moreover, most college students don’t officially declare their major until their junior year.</p>