Some people think that the most important period in a person's life is one's twenties. However, in my opinion, other ages are also as important periods and people do not know when they experience their golden ages.
To begin with, other ages are also as crucial period in a person's life. This is because that In the past, past people lived only for a short period. However, today, people even live until one hundred years old. So, in addition to twenties, people concerne about how health they live in their live. (무슨 의도로 이 맥락에서 나오는 얘기인지 파악이 안 됩니다.) For example, there were a poll conducted by Tom Rath, the director of the Gallup Organization with 200 collage college students as respondents. The purpose focus of the survey was to understand the consensus view about persons's longevity the human life span in the modern world. The overwhelming 78 % 78% (띄어쓰기 없음) replied that they ranked all ages over twenties (무슨 의미인지 너무 모호합니다). The majority of the respondents responded that they focused on how they live their lives healthfully (20대가 얼마나 중요한지를 얘기하는 이 주제와 무슨 관련?). They added that their twenties was not much less essential in their lives. This proved that it was not necessary one's twenties for people (문법이 안 맞는데 무슨 의미인지 파악하기도 어렵네요).
On top of that, one does not know when his valuable golden age arrives are arrived. This is because that it does not to take a genius to know that A person's golden age may be late or early, so people might experience this age later than their twenties in their late age. For instance, my cousin studied throughout his twenties in order to be lawyer. Although he spend spent his young age youth on studying laws, finally, he became a lawyer when he was thirty years old. However, now, he works lively and busy. He earns a lot of money every year, so he says his golden age is right now.
To sum up, the most important period in a person's life is one's twenties as well as other ages (첫 point를 제대로 요약해주세요) and everyone do not nobody knows when their success best time comes true. In this regard, I disagree with the statement that the most important period in a person's life is one's twenties.
Writing 0-30 scale
Fair (21-22)
각 point마다 설명이 제대로 안 되고 있습니다. 큰 주제(20대가 제일 중요한 시기는 아닐 수 있다)를 뒷받침하기 위한 두 point를 설정했으면, 본문 두 문단에서 이 두 point를 충분히 논리적으로 설명을 해주세요.
여러 표현 및 문법 면에서 어색한 부분은 본문에 수정했으니 역시 참고하세요.