My name's Trinidad, I'm from Argentina, MendozMendoza, Argentina.

It would be more natural to put the city first.

My first language, of course, it's sSpanish.

Always capitalise languages, eg. English, French, Chinese.

I've loved eEnglish since I was little, but I never went to a placnywhere to learn it, I just learned alone by watching series, movies or hearinglistening to songs.

I've changed "place" to "anywhere" to make it sound a bit more natural. Same for "listening to music/songs", as listening implies intent while hearing is more passive. As an example, you would purposely listen to music or a speech, etc, but you would hear a siren, or shouting, or any sort of background noise.

Last year, was the first time I went to an Instituteformal classes, because I needed to prepare myself for collaege, - I want to be an English Ttranslator.

No need to capitalise institute unless you were writing out a name, eg. the Institute of English. However institute alone is a bit vague so I changed it to formal classes, which is what I am guessing you meant.

Collage is a type of art made by sticking pieces of paper together. College is a school or university.

I added a hyphen to make the sentence smoother, as there were too many commas. Now, you have the first part of the sentence (talking about you taking classes) leading to the final point of the sentence (your goal of becoming a translator).

No need to capitalise translator here either.

Now, my level it's intermediate but iI want to improve my writings.

I think if you are referring more generally about your skill level, you would just say "my writing [skill]" but if you were referring to a collection/body of work you have done, you could say "my writingS".

Don't forget to always capitalise "I".