Letter please correct

You are studying overseas. You need to return to your home before the end of the semester for a family event. Write a letter to your supervisor in your letter:
Request time off
Explain why you need to leave early.
Reassure him/her that your studies will not suffer.

Dear Sir,
I would like to bring your attention towards  my concern. I am a computer science student in section 4. I would like to inform you that my sister is getting married and I will have to go home for her wedding. My exams will be over on next week on Thursday. I have prepared for exams and I am sure that I will get good grades in every subject. The wedding will take one week including all function and parties.

I request you to grant me leave for one week and I will return by the end of this month. I assure you that this will not affect my preparation for next term and I will complete all my assignments on time. I will be leaving the campus on same day when I will take my last exam. Since I will be making all the arrangement of wedding that is the reason I have to leave early.

Yours sincerely
XYZ

Good Job. Keep Writing..