Here are a few things I would change, working off of Dodger's original translation:
Well... I'm going to write a bit about what I want to do in my/the future. Firstly, I'm Marcelo, I'm 20 years old and I am studying business administration. This is my first year, since I have just started... I want to become an administrator and then travel abroad; though I'm not sure where to go yet, it will be an English-speaking country. I'm considering travelling to the United States, in order to practice my English and get to know/learn about the culture that influences most of the world.
I might be wrong, but I take "knowing a culture" to mean having a profound understanding of that culture's inner workings and subtleties. In most contexts, "knowing" is much more of a state than a process. If I wanted to describe the process of learning about a culture, I would favor "getting to know a culture" over "knowing a culture" (unless that was the intended meaning).