You are not supposed to end a sentence with a preposition. It is a nitpicking sort of rule, but you might as well obey it in this kind of essay:
Diversity is something
to which we all need be exposed and
for which we should all have appreciation.
Actually, the first few sentences are sort of weak, because they are just statements of the obvious. I think you should start here:
Students who come from
diverse backgrounds and lifestyles can share their experiences, and we can learn
from one another. I attend a high school with a multifaceted, colorful class of students and personally...
Hey, the personal anecdotes are great!! I think the last paragraph should be a little longer, though. Just a little more reflection in that last paragraph.
Kevin, EssayForum.com