Undergraduate / "It's rare for someone so young to contract shingles, but it's still possible" - I stuck in there... [14]

Maybe you could be more concise in the first part describing your grandmother's visit.
Anyway, I think it's a very great essay and your writing is fluid and vivid. Don't get too disheartened by the rejection, and your essay is not your entire application. Good luck on your application process. :)

Writing Feedback / Considerations and factors influence the universities budget allocation to meet students' demand [2]

Try to type as much as possible within thirty minutes, maybe 700 words and avoid using one word twice or even more.
E-rater will score your essay based on word count, vocabulary, sentence structures and coherence.
Use some phrases, such as to be more specific, to put it in another way, that is to say, what I mean is to add up coherence.

Undergraduate / My belief, that Indonesians are not inferior in science, has been proven by my own bestfriend. MIT [5]

Hi, I'm Zhang from China. It seems that you forgot to give us the essay prompt, preventing us from providing you with useful suggestions.

To be honest, this essay isn't effective and pursuasive enough to get your admission to MIT. You need to improve your writing styles first, as you are using plenty of words while conveying limited information about yourself. Second, the description regarding your peers and Indonesian educational system should be no more than several sentences. And the most importantly, elaborate on your passion for MIT. Ask yourself what specific opportunities available here meet your aspirations and what you may contribute to the MIT community. Do more research by visiting MIT and other websites and focus on yourself, instead of your friends or graduates from your high school.

Hope my advices are helpful for you.