Our planet, which may be like no other, harbors billions, if not trillions of species of flora and fauna.
This first sentence is a statement of the obvious. I bet you can do a little better! It is not good to start the paper with a statement of the obvious, because the reader might lose interest right away and stop paying attention. When that happens, it's difficult for the essay to suddenly catch her or his attention again and make a strong impression.
genuinely marvelous.
This does not say anything of real substance. The reader is likely to already know about the Fibonacci sequence and the spirals, etc. I think you should distill this paragraph into one powerful sentence that is packed with meaningful ideas, and then use the rest of the paragraph to tell about the idea you challenged.
Until the ninth grade, I was just another student: normal, without any particular passion.
And what are you now, a superhero? This sentence could be better if you omit the implication that normal students have no particular passion.
I am trying to criticize, but I have to admit you really have a great writing style...
which at first I didn't find interesting and didn't prepare for.
You have a few errors here, like wrong use of 'which' and ending the sentence with the preposition 'for'...
I think the whole essay should begin here, with the first interesting part:
A friend recommended me to buy a series of books called The Art of Problem Solving and join FLSAM (Florida Students' Association of Mathematics). Once the books arrived, I began...This part tells a story, recommends a book series.. it is genuinely interesting! The parts above it cannot be interesting to anyone because they don't say anything specific that the reader does not already know. I think that bold sentence above should become the first sentence of the essay.
Try restarting there, and use the extra space to dig deeper and explain a few short term goals related to the idea in the essay.
Capitalize Internet.
Yeah, I really think you should start with that bold sentence and let MORE of the essay answer the prompt question. And btw, some people who are spiritual would argue that the golden section is evidence of intelligent design! Or at least intelligent transformation as we go along.