The fact that you are a freshman and didn’t do what you needed to do to succeed because you decided you don’t like parts of being a psychology major… that’s not very convincing. You’re a freshman, you weren’t even deep into your major courses in Psych. What happens the next time you take a course that you decide you don’t like, or don’t feel a deep connection to? Frankly, I’d be less than swayed if I was reading this as the person making the decision on your dismissal. And I’d omit that whole second paragraph. It does nothing to help your case.