Shachar, there is room for improvement in your essay mostly because you deviated more than once from the essay prompt. This is not an autobiographical essay, to mentioning your experience in the navy is not relevant to the essay. It is also the main reason why you went over the required word count. If you start the essay immediately at this particular point;
I'm attracted to northwestern's Financial Economics Certificate program. I spent the last several years investing my own money and although I did beat my benchmark which was the S&P500, I believe that attending this program will take my business understanding to the next level and help me develop as a professional.
you will have established your answer the the prompt immediately that requires you to connect the undergraduate school you are applying to with the unique qualities of Northwestern University. Follow it up immediately with;
I wish to become an entrepreneur. I've the needed initiative, but I'm missing the academic education that will broaden my horizons and teach me how to carry out enterprises. I believe Northwestern's qualities will enable me to prosper as a person and as an entrepreneur. Furthermore, I think that I can contribute to its cultural diversity and be an integral part of it.
and you will have established the qualities that you share in common with other Northwestern students. Adding this following will establish the way that you plan to utilize the opportunity to study at the university:
I also love that Northwestern has students from all over the world because it produces a mixture of cultures. I traveled alone around the world for a year, met people from almost every place on the globe and learned many things from them. In addition to perfecting my English, I learned Spanish, Polish, and to speak a bit of many other languages. I wish to continue to expose myself to different cultures and I would love to share my experiences with my peers.
If you will kindly revise your essay to reflect these changes, I believe that you can be assisted in further strengthening the essay within the proper word count. Don't worry about the actual word count while you are revising the essay. The word count, grammar problems, and other situations existing within the essay will be fixed as the content of the essay is revised.