I could spend the entire night talking about how what students in Korea go through during their teens. I don't even know where to start. Here's my story. I spent my teens, especially my high school years, working hard to get good scores grades on the my exams and finally go to get accepted into a good university. That was my goal. I hadn't thought about my life after I entered a university. I would say I was just a studying machine. I would get up before 6 in the morning to catch the school bus and wouldn’t get back home at until almost 11 pm. That was my routine for 3 years. As a result, I got to entered a good university. I survived the competition. It's been 8 years since then. Now, even though I have a stable job, I'm struggling to find what I really like and what I'm going to do in the future. I didn't even question my exhausting, suffocating school and life back then. It's difficult to cram what I'm trying to say in this short paragraph. Ha! Cramming. Sounds familiar. I'll continue on the next note. Maybe.

Notes:

As always, it is almost perfect grammatically! I mostly changed the nuance.

1. If it were “how”, you would talk about emotions, not events.
2. Because University is the reason, “and” turns into “to”.
3. Studying machine is bragging in English. If you want to seem sad, you should write “machine that just studied”.
4. Teens is time. High school is place. So you change “in high school” to “high school years” to change it to time.
5. If you are doing two things, you should have the first one first. “Wake up” then “get home”
6. “Wouldn’t ____ until” shows how late it is.