Sounds like you already have your topic. And your outline.
Which just leaves...
actually writing your essay.
Hahahahaha ... how about:
2. more money
3. give me your money
Hahahahaha ... thanks ... but it is, sadly, the truth ...
1.why the entering college test is important.
Because the illusion of meritocracy is what keeps the masses from slaying the masters.
2.why 18years old is important.
That's when one becomes legal for porn in the US.
3.why the first job is important.
Because if you don't take that public relations internship when you're an undergraduate or recent graduate, you will have little choice other than to go to China and teach English for three years.
Marx wrote something similar, about the choice of profession by a young. The essay has many rhetorical arguments bla bla..... maybe can inspire you