hey..!! Can anyone tell me the last date to fill class 12 admission form (CBSE).. [from school ofcourse]

School principal is saying that the last date was 25 August 2014, so i wont be able to take admission. So please help.. Its URGENT!!

P.S- I want to give class 12 improvement in all subject (so category- full subject) and as a regular candidate not private. So if you want to suggest me something..??

Oh and also tell the last date of "Updation of Contact Details of Students" for school..