That 1/3 of major changes tracks the number of students who declare a major and then change. When you look at statistics that include students expressing an area of interest and switching before the initial declaration of a major (some colleges do not allow incoming students to declare a major), the percentage is much, much higher, as high as 80% (in my own house’s small sample, it’s 100%). If it you enjoy doing it, go for it, but all your efforts may be premature or for naught.