but I later understood that everlasting feeling of joy, accomplishment and self-worth that making a difference in someone's life was when, in my turn, was helping friends of mine with assignments in class, or even people I didn't know crossing the street, carrying shopping bags to their doorstep.
I only copied the second half of this really long sentence. Why not make it a separate sentence:
I later understood when I experienced the feeling that comes from making a difference in someone's life, feelings of joy, accomplishment and self-worth...when I helped friends...etc. etc
I firmly believe that my eagerness to learn, help people, and personality along with my efficiency will benefit any of my future employers
If this essay is for an admissions letter, you might want to tailor the ending to how you will be an asset to the school.