I'm cCeren from tTurkiye.

"I'm" is a contraction, it means "I am" but is shortened to one word. You would also capitalise your name and the country you're from.

I just graduated forom highshool.

"graduate" is an action. "graduated" means that you did that action in the past. Minor spelling mistake with "from".

I Willam going to go to university and my department is eto study English t. They Wwill teach in one year, but ıI don't want to be forced, and ofcorse ıI want to be a watch films and series with no subtiteles.

It isn't necessary to capitalise "will" unless it is referring to someone's name. As a name, "Will" is a shortened version of the name "William".

I don't know if you meant to say that you're going to go to university in one year, or if you're trying to say that you will study English for one year.

Small spelling error with "subtitles".

Anyway ı, I have to contiunenue to talk about myself.

Just a minor spelling mistake. You could also say, "I am going to continue talking about myself." or "I have to continue talking about myself."

In highschool i, I was a math and tTurkish student.

"I" should be capitalised. You could also say, "In highschool, I studied math and Turkish."

In tTurkiye we separate from math and sciene , like mece. I studied math and tTurkısh , while other students studied social sciences students and language students .

I'm not sure what the last part of the sentence is meant to mean. Sorry if it's not what you intended for it to say.

After that part, we to enter a univesarsity exam t. This is realyly, really so Hhard. if you have time, you have to beshould take oa look .

Just a few spelling errors and some punctuation.

Some subjects Anstudents from other countries students are learn in üuniversity, but we learn in highschool at only sixteen or seventeen years old.

You could also say "Some of the subjects we learn in highschool at sixteen or seventeen years old are only taught to students from other countries in university."

This isIt's a long story o. Ours educatiaon its not going well.

Our economy is not going well tooeither, but education is moreuch more important than economy because this fixing it is too much Hhard.

"Our economy is not going well too" will be understood, but it's better to say "either" rather than "too" in this sentence.

"too much hard" could be changed to "difficult".

I Ggot into different topics.

"got" doesn't need to be capitalised.

AI actually ı want to talk about my own university departmaent, but iI'm tired .

Next time ı, I'm gonna explatioin with more details.

"gonna" works fine, you could also say "going to" if you want to sound more professional.

I will talk about myself.

I'm cCeren from tuTürkiye.

I just graduated forom highs school.

Past tense. Spelling. High school is two words. That said, this is a common native mistake as well though.

I Wwill go to university and my department is ewill be English t. They Wwill teach in it in one year, but ıI don't want to be forced and ofto study. Of course ı, I also want to be able to watch films and series with no subtiteles.

Some spelling, capitalization and sentence structure tweaks.

Anyway ıs, I have to contiunue talking about myself.

In high school i, I was a math and tTurkish student.

I am not sure what

In tuTürkiye, we separate from math and sciene , like meocial sciences. For example, I am in math and tTurkısh , social sciences students and language students .ish.

I took some liberty here because the sentence was confusing. I think you are saying that the departments are divided up, but it seems like it was being said twice?

After that part we to enter, we take a univesarsity exam t. This is realyly, really so Hard ihard. If you have time, you have to be take oa look .

This reads a little stiff, but I tried to keep it close to the original sentence.

Some subjects Another countriey's students are learn in üuniversity, but we only learn in high school until we are only sixteen or seventeen years old.

This is lLong story short, ours educatiaon its not going well.

Our economy is not going well too, but education is more more important than economy because this fixing it is too much Hhard.

I Ggot into different topicsa little sidetracked.

Shorter, more natural sounding way to say the same thing.

AI actually ı wanted to talk about my own university departmaent, but iI am tired .

Next time ım gonna, I'll explatioin with more details.

I tTalk aAbout mMyself

Be sure to capitalize your titles for professionalism's sake.

I'm cCeren from tTurkiye.

Add an apostrophe when trying to make a phrase (e.g. "I am") into something shorter (e.g. "I'm"), if you can. Also, capitalize names like your given one and that of your country.

I just graduated forom highs school.

Here, I fixed a bit of your spelling to clarify that this action happened in the recent past.

I Wwill go to university, and my department is eEnglish t. They Wwill teach it in one year, but ıI don't want to be forced and ofto study. Of course ı, I want to be able to watch films and series with no subtiteles.

I added "to study" because I assumed that's what you meant to write first when talking about not being forced to do something in your department or major. Apart from this, you just had some minor spelling, punctuation, grammar, and capitalization errors.

Anyway ı, I have to contiunue talking about myself.

Capitalization and punctuation errors aside, I think you should look into compound verbs (e.g. [Verb 1] [Verb 2]-ing) and see how different types of them can be used; I bet the sources you'll find in this respect will be much better than any explanation I could give.

In high school is, I was a math and tTurkish student.

I just fixed some punctuation, spacing, and capitalization errors here to make this sentence more readable.

In tTurkiye, we separate from math and science , like me with math and tTurkısh , social sciences students, and language students .

Even with the corrections I've made, I'm not completely sure what you mean here. Do you mean that Turkish students major in separate fields like math, science, social science, and languages even in high school?

After that part, we have to enter a univesarsity exam t. This is realyly, really so Hard ihard. If you have time, you have to be take oa look .

I don't think you have to add in "so" if you already have an emphatic phrase like "really, really" in place. I assume my other corrections can also make this sentence clearer.

Some subjects Another countries are learnOther countries learn some subjects in üuniversity, but we learn them in high school at only sixteen or seventeen years old.

I just think my rearranging and additions make this sentence easier to understand.

This is a long story, but ours educatiaon its not going well.

You could also say "Long story short" instead of "This is a long story," like what I've written here.

Our economy is not going well too, either, but education is more more important than the economy because this fixing is too much Hhard.

If something is also going negatively in comparison to something else, use "either" instead of "too." The other deletions and additions I made should hopefully make this sentence easier to read.

I Ggot into different topics. I actually ı wanted to talk about my own university departmaent, but iI'm tired n. Next time ı, I'll explatioin with details.

If there are contrasting topics within one sentence that you're trying to write, you can just split them up like I've done.