I successfully changed my major myself.
Taking the average grade (GPA) of the first semester as the threshold, you can take the professional examination if you meet the requirements. If you pass the written test, it's an interview. If you pass the interview, you can change your major.
If you are not satisfied with the accepted major and want to change majors, you must make up your mind to prepare as soon as possible. Many students in my class have been seriously preparing to transfer to professional examinations, learn advanced mathematics, and do problems. Starting from the second semester, and it will be much easier after passing the written test. Then prepare for the interview, from self-introduction to understanding your major and your career planning. Meet the teacher's question with confidence.