My eExperience wWith the English language

I have been studying English since I have memory, mfor as long as I can remember. My parents put me in a bilingual school when I was 6, and I graduated with a B1 English level at 17 years old.

"for as long as I can remember" is the set phrase for what you're trying to say.

The thing is that I got stucked in at that level for a long time, because I was admitted at the Uto university and stopped practicing English until this year.

"admitted to university" is technically fine, but it does put a little more emphasis on the act of being admitted to university (like you were accepted to the university but may not have actually attended yet). It's more common to say "I went to university" when you mean you actually attended.

Two months ago, I started to practicing again, learning new things and retakviewing vocabulary and stuff that I had forgotten.

My goal is to reach C1, or at least B2 level, to get enrolled in an international job, but it is costing me too much to get back to the level I had before :(

My experience with the English language

I have been studying English since I have memory, mfor as long as I can remember. My parents put me in a bilingual school when I was 6 and I graduated with a B1 English level at 17 years old.

1. “Since I have memory” isn’t really something we say, I think you’re trying to use the phrase “for as long as I can remember”.
2. It also seems like you should end the sentence after that phrase, it has not conjoining word (and, but, so) and it’s very run on-y.

The thing is that I got stucked in that level for a long time, I was admitted at thea University and stop practicing English until this year.

1. “Stucked” isn’t a word, “stuck” itself is already in the past tense. It’s the past tense of the verb “stick”.
2. You haven’t mentioned a university at all up until this point, so using “the” sounds odd. You said use “a” instead.

Two months ago I started to practicing again, learning new things and retak-learning vocabulary and stuff that I forgot.

1. You don’t need to word “to” here, as you’d only need that if you were using a verb in it’s infinitive form
Ex: “I started to practice”
2. The way you phrased this part of the sentence is a bit odd, so I rephrased it to make it make more sense.

My goal is to reach C1 or at least B2 level to get enrolled in an international job, but it i’s costing me too much to get back to the level I had before :(

1. “To get enrolled in an international job” sounds weird, we only really use the word “enroll” for education-related things like enrolling in a school or enrolling in a class. You can simply just say “get an international job” but you could also say “get accepted at an international job”.
2. I thought that adding the conjunction “it’s” would make the sentence flow better.

My eExperience with the English lLanguage

(1) This is a minor issue, but all words are generally capitalised in a title, with the exception of certain special words like short prepositions ("with") and articles ("the"). However, whether you capitalise "with" or not depends on the style guide you follow. Some consider it short, while others don't.
(2) We either say "the English language" or just "English". This is because in the phrase, "language" refers to a specific language in particular, so we use "the" to indicate that.

I have been studying English since I have memoryfor as long as I can remember, my parents put me in a bilingual school when I was 6 and I graduated with a B1 English level at 17 years old.

"Since I have memory" is understandable, but not really a phrase we use. The expression you're looking for is "for as long as I can remember".

The thing is that I got stucked in at that level for a long time, I was admitted at the Uto university and stopped practicing English until this year.

(1) "Stuck" is the past tense of "stick". "Stucked" is not a word.
(2) When talking about skill levels in particular, as you are doing here, "at" is more appropriate than "in".
(3) The collocation is "admit to (a school)".
(4) The use of "the" and the capitalisation of "University" is odd, since you've not specified which university you are referring to in particular before this. By the way, you don't have to say "admitted to a university" either. In the phrase "admitted to university", "university" represents the general and abstract concept, rather than a specific school, and an article like "a" is not expected.

Two months ago I started to practicinge again, learning new things and retakvisiting vocabulary and stuff that I'd forgotten.

(1) Alternatively: "I started practicing again".
(2) "Retaking" might be used in a phrase like "retaking an exam". "Revisiting" is the word you're looking for. Alternatively, you can use "relearning", but you'd already used "learning" right before that, and it's good to use more varied vocabulary.
(3) The past prefect ("I'd forgotten") might be more appropriate here, since you forgetting said stuff occurred before another past event (you starting to practice again).

My goal is to reach C1 or at least B2 level to get enrolled in(into) an international job, but it is costing me too much to get back to the level I had before :(

"Enroll" is not used when talking about jobs, but rather schools and courses: "I enrolled in medical school"; "I enrolled in the language course", etc. The phrase you're looking for is "get into a job" or "get a job".

I have been studying English ever since I have memory, mcan remember. My parents put me in a bilingual school when I was 6 and I graduated with a B1 English level at 17 years old.

The thing is, that I got stucked in at that level for a long time, I was admitted at theto University and stoped practicing English until this year.

Two months ago, I started to practicing again,: learning new things and retaking vocabulary and other stuff that I had forgotten.