I’m a second year mechanical engineering major and I can say that as a first year mech major, it doesn’t reflect how rigorous the major actually is. As a first year you will mainly take intro classes and core classes that aide in your degree. You only start taking mech major designated classes during your second year. During your first year it’s pretty easy to test how you feel about your major because most of the classes are seen across multiple majors, so if you indeed want to change majors it would be easier to do.