<p>You will have many prerequisites to complete before the department will probably accept you (lower division linear algebra, DE and calculus III).</p>
<p>Those lower division courses can either be easy or difficult depending on the rigor of your professor; more likely they will be easy since at UCLA you will probably be in a class of 100 students taught by a TA.</p>
<p>Afterward, you will begin upper division coursework starting with linear algebra and analysis, and that is when things will change completely, and you will be forced into deciding (you will have no choice) whether math is fit for you.</p>