Проверьте, пожалуйста, английский текст на ошибки.

Лучше говорить for a company . Почитайте вот здесь о предлогах с этим словом. http://www.englishforums.com/English/PrepositionsWorkCompany/cxxrc/post.htm
И очень интересная статейка для двух вариантов for a company или at a company :)
http://ezinearticles.com/?Do-You-Work-For-Your-Company-Or-at-Your-Company?-There-is-a-Big-Difference!&id=2508044

ПОВТОРИТЕ условные предложения
HELLO!
My name is Yura and I HAVE recently entered the liceum №1.
I'VE DONE it, because I am going to beCAME A web-programmer in future.
I think that TO BE A web-programmer is A good job and it will be popular for a long time, because the Internet develops every day, IT has and will have a large audience of users.
I think I will enter a university when I XXXXX finish my studies at the liceum.
So I have a centralised testing in June, which I XXXXX must PASS WITH A XXXXX good mark to enter the university.
When I XXXXX finish my studies there, I will work in some company to STORE UP SOME XXXX experience.
And after that I think I will create my own company to develop Internet-sites.

Good day!
My name is Yura and I have recently entered the liceum №1.
I have chosen it because I am going to be a web-programmer.
I think this job is very interesting and it won't lose its' topicality, because the Internet is evolving rapidly and its audience is growing every day.
I'm going to enter a university when I finish my studies at the liceum.
I have a centralised testing in June, which I will have to pass with a good mark to be able to enter the university.
When I finish my studies there, I will work in some company to gain experience.
And after that I expect to create my own company, which will specialize on developing Internet sites.
I have a long way to go, and many difficulties are lying in wait for me, but I'm going to overcome them all!

такое ощущение, что второй вариант переводили через он-лайн транслэйтор- каким образом здесь вообще условные предложения Вы приписываете повторить? - какого именно типа?
первый перевод намного корректнее (ибо Ваш вариант меняет смысл некоторых предложений) , богаче лексикой и эмоциональной окраской, а уж простите Ваша поправка -после чего дочитывать даже не стала I'M GOING TO BECAME - ГОВОРИТ О МНОГОМ- ибо правильный вариант BECOME (а как у автора- не ошибка использовать BE- и не нужно это поправлять на неправильный вариант)
к автору пожелание:
1- is growing more and more every day (так Вы обоснуете свой Present Continuous)- больше ни одной ошибки и помарки не наблюдаю!