I like it mostly.
I know that any college I go to will be prestigious; this I am sure.
^Sounds arrogant. You should probably reword this.
All of the colleges I am applying to have nice looking campuses, a medium sized student body, and challenging classes.
^You don't need to mention the other schools you're applying to. It kind of sounds like you're telling Stanford that if they don't accept you, other nice schools will.
I know Stanford University meets my standards for quality education and-excuse my modesty-I know I meet Stanford's standards.
^Alright, I like this attitude but admissions will probably not like it. It's for them to judge if you meet Stanford's expectations.
I know that Stanford's selection process focuses on the cohesiveness and uniqueness of the student body, and that is what stands out the most to me.
^Delete this and tell them more about what stands out most in you.