Hey Nicolas,

You write reallly well! But I've made some changes here so you can see how it would read with a bit more of "English flair."

Hope it helps! :)

Sincerely, 

Anthony

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Hello Everyone,

As a native French speaker, I'd like to introduce myself by saying a few things about my ideal future job.

In school, English was definitely the subject that appealed to me the most. Whether it is vocabulary or pronunciation, I try to improve every day.

As a matter of fact, my dream is to live in America. The country has always attracted me due to its culture. I want to be a French teacher there, or something like that.

Some people discourage me by telling me it's impossible or that I'm influenced by fiction characters in a series. They don't reaize how important it is to me that I fulfill this wish.

That's why I'm here today, writing about myself. I think this website could help me.

Hello, Nicolas! Nice to meet you. It's exciting to hear about your dream to live in America. Don't listen to others. Just follow your dream.

Please find my corrections for your entry below.

Original:

What I'd like to be

Hi everyone, I'm french and as an introduction for myself I'm going to write a few things about my ideal future job.
English is definitely the matter at school that appeal me the most, and I try to improve it every day, whereas it is about pronunciation, or vocabulary.
As a matter of fact, my dream is to live in America. This country always attracted me, due to its culture. I want to be a French teacher there, or something like that.
Some people discourage me by telling me it's impossible or that I'm influenced by fiction characters in series. They don't figure out how much it is important to me to fulfill this wish.
That's why I'm here today, writing about myself. I think this website could help me.

Edited:

Hi everyone, I'm French and as an introduction to myself, I'm going to write a few things about my ideal future job.
English is definitely the subject at school that appeals to me the most, and I try to improve it every day, whether it is my pronunciation or vocabulary.
As a matter of fact, my dream is to live in America. This country always attracted me, due to its culture. I want to be a French teacher there, or something like that.
Some people discourage me by telling me it's impossible, or that I'm influenced by fictional characters. They don't understand how important it is to me to fulfill this wish.
That's why I'm here today, writing about myself. I think this website could help me.

Notes:

Great job on this entry, Nicolas! Overall, I had no trouble understanding what you were saying. The others in your entry were mostly minor. For the most part, the corrections I made were to make your entry sound more natural. For instance, I changed "matter" to "subject," in order to better convey your meaning in a way we might express it in the States. 

If you have any questions about my other corrections, please let me know.

Best,

Charlie