Я не буду исправлять ошибки, слишком много работы...Лучше переведу, а вы, уж, там сами разберётесь!

I went to school when I was seven (years old). I'll leave\finish it in two years.
A school uniform isn't worn at our school, you may come in casual clothes.
There is a lot of homework (to do), but I try to do everything and hand-in in time.
I'll take MY first exams this year, Russian (= the Russian language) and Maths are mandatory\obligatory subjects, and there are two more to select (there are two more to your choice.)
What kind of your school and what problems do you have there?
What were you interested in your childhood? (= What did you go in for in your childhood?)
Do you collect stamps?
What do you go in for now?

Wear a school uniform is very important! Firstly it is the rules of the school. Secondly this form does not make you a bright, yet it is elegant and highlights your business style. По поводу формы))