Кто знает английский???проверьте мой небольшой топик о себе!!!!внимание на артикли и предлоги!!!

I was born in Moscow on a Saturday, on the September 7th 1991. I’m an only child. My mother is an engineer, my father is an economist. I attended general school. In college I majored in medicine (medical school - это медицинский колледж? в английском medical school, это медицинский факультет в университете) . I am now studying chemistry at the university. I have written a chemical Olympiad with good results therefore I am studing chemistry. I like my life, I like an active way of life, I like to make friends with different people. I very much like to read classic literature, listen to music such as the Rolling Stones. When I have enough money, I want to help children of poor countries. I think I am a good person, but I can’t always get what I want

I was THE only child - если единственный, то и артикль нужен определенный.
General school? Вы имеете в виду общеобразовательную школу? Тогда secondary school.
AT the academy.
Я бы сказала "I succeded at the olympiad"
Не стоит в одном предложении употреблять один и тот же глагол, замените его или разбейте предложение на несколько. Например: "I enjoy my life, i prefer active lifestyle. I like to make fiends...."
I love reading classical literature, listening to music, the Rolling Stones for example.
FROM или IN poor countries
but i don't always get what i want

I was born in Moscow on The 7th of September,1991. It was Saturday. I’m THE only child in my family. My mother is an engineer, my father is an economist . I studied at school then at medical school, now I STUDY at chemical academy. . I WROTE a chemical Olympiad with good results and entered this institute therefore. I like my life, like an Active way of life, like to make friends with different people. I like to read classic literature VERY MUCH and to listen to music such as Rolling Stones. When I have enough money, I’ll help children IN poor countries. I think I am a good person, but I can’t always get what I want

All is OK, I think!

I was born in Moscow on The 7th of September,1991. It was Saturday (это бы конечно можно было убрать...))) . I’m THE only child in my family. My mother is an engineer, my father is an economist . I studied at A (вы добавляете определение, это уже не абстрактное место учебы, а одна из класса общеобразовательных школ) general school then at A (то же самое-вы причисляете предмет к классу) medical school, now I am studying in A chemical academy. .УБРАТЬ= [I had written a chemical Olympiad] (так не говорят, кроме того в англ. Олимпиада используется только в значении греческих игр) скажите участвовала в олимпиаде по химии- I participated in a contest in chemistry. As I had passed it with good results I entered this institute (извините, что изменила структуру, но так звучит по-английски) . I like my life, like AN Active way of life, like to make friends (с разными людьми не добавляйте-избыточно, понятно, что не со зверьми и что с людьми не одними и те же) . I (very не используется с глаголами само по себе как в русском, после него обязательно нужно наречие, ставится оно только после глагола) like to read classic literature VERY MUCH, listen to music OF SUCH GROUPS AS(здесь вы сравниваете-но роллинг стоунс - это не просто музыка, а группа, поэтому надо расширить предложение) Rolling Stones. When I have enough money, I’ll help children of poor countries. I think I am a good person, but I can’t always get what I want ( в конце немного несвязано, но в общей сложности интересно)))

роллинг стоунс напиши с большой буквы... правильней будет.. .
ещё если ты эт будешь писать, то фразу " on The 7th of September,1991" пиш прост on 7 September, 1991
А так всё ОК!