I'm writing a short article sending to my school newspaper. It doesn't need to be very formal. In fact, I think an informal way might be better.
Please look through this and correct grammar errors, or, may be, rewrite some of the sentences. Also, if possible, please make some comment about my writing. This's my first time writing an article like this, which I really don't know much about it. Thank you so much.

Did I make the right choice?
Becoming an exchange student? some of you might think it's a crazy idea; why someone who is a “Dek-Wit” would want to be so far away from home, and miss the most important year—M.5—in his high school life. You know what? I once thought like that too. It's not an easy decision at all. In fact, it was the biggest decision I've ever made. But, it is also the best decision too. I've never regret of having chose to spend a year in the the US. It's such a remarkable experience. Imagine yourself staying in a house of a native-speaking family who neither know you nor is a relative or yours. You can berely communicate with them; can't even tell you what you kind of food you like or dislike; and neither do they understand most of what you say(This may sound funny but it's really true). But one day! all these things just seem so easy to you. Now you're not only be able to express your thought but also be able to read and write. Although, my English has improved a lot in a year, I don't want you to think that to be an exchange student is just to learn a language. The most valuable thing I'd learned was, in fact, the culture, whereas the language is just part of it. Also, I got to do things I'll never have a chance to do like made my own schedule, performing a show on a stage, and going to the Prom(the biggest high school dance). In addition, I got to realize that in this world fulled of wars and conflicts, it's so beautiful and so fastinating; and there are so much to learn out there. Lastly, I truely say that a year in America has changed my life. I got to better my English, open my world-view, and make foreign friends. For anyone, who has a strong desire to learn more about other countries and cultures(including language), WHAT YOU ARE WAITING FOR!, grab this precious chance, and follow your dream. And your life will never be the same.
Hi there. I think that your first publication is very very good. Where are you from? Where do you want to publish it? But some things seems suspicious, i meant using tenses and grammatical constructions.

Do You know what? - use do is necessary, but in informal way of writing skipping is possible

It's not an easy decision at all. In fact, it was the biggest decision I've ever made. But, it is also the best decision too - using word decision many times isn't good idea and makes your level down.

I've never regretED

barely

speaking family who neither know you nor is a relative or yours - Simply, on my own say: speaking family who neither know you nor your family. =)

and neither do they understand most of what you say - construction contradict word order in sentence. Simply to say,if you want to use such construction: There is no way they can understand me.

Also, I got to do things I'll never have a chance to do like made my own schedule, performing a show on a stage, and going to the Prom(the biggest high school dance) - sequences of tenses. I did such things which I never should do like made ....

world fulled - is fulled

truely -truly

open my world-view - my advice - use "open my mind" ))) and use made instead of make (sequnce of tenses_

WHAT YOU ARE WAITING FOR!, - what are you waiting for?

In the end, I hope that this advices should help you in hard work of being good in English.. Sincerely your's =)
Thank you for correcting my essay. I come from Thailand and this article gonna be published in my school newspaper. I have been working on my writing skill for a while. Sometime, I fell like I want to give up because I always make many silly mistakes like basic grammar and spelling. Thanks a lot for your compliment. It's very kind of you. You might not know this but it really means so much to me.
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I don't know whether this might help, but, juz give a shot anyway....

[..]In fact, it was the biggest decision I've ever made. But, it is also the best decision too.(In fact, it was the biggest but also the best decison I have ever made)

I've never regret of having chose(regretted chosing) to spend a year in the the US.

Imagine yourself staying in a house of a native-speaking family, who neither know you nor is a relative or yours.(nor be) You can berely communicate with them; can't even tell you(them) what you(no "you" here) kind of food you like or dislike; and neither do they understand most of what you say

But one day!(no need of exclaimation mark) all these things just seem (to be) so easy to you. Now you're not only be able to express your thoughts but also be able to read and write.

Although, my English has improved a lot in(I think "throughout" is better) a year, I don't want you to think that to be an exchange student is just to learn a language.

The most valuable thing I'd learned was, in fact, the culture, whereas(and) the language is just part of it. Also, I got to do things I'll never have a chance to do like made(making) my own schedule, performing a show on a stage, and(or) going to the Prom(the biggest high school dance).

In addition, I got to realize that in this world (is)fulled of wars and conflicts, it's so beautiful and so fastinating( I think the two clauses is not relevant to each other; they have opposite meanings); and there are so much to learn out there.

Lastly, I truely(truly) say that a year in America has changed my life. I got to better my English, open my world-view, and make foreign friends. For anyone, who has a strong desire to learn more about other countries and cultures(including language),

WHAT YOU ARE WAITING FOR!(what are you waiting for?), grab this precious chance, and follow your dream. And your life will never be the same.

These're juz my suggestions