Thanks for reply.butActually my D.O.B is 23 July 2002 .but by mistake in my birth certificate there is 2003 .so what should I do? Please let me know 

Hi ,
Changing the date in birth certificate is no easy task , the process varies from state to state ,if you likely from Tamil Nadu , it's so easy because I'm also faced the same problem like that .just I got signature from government doctor that I was born on the date, required for the SSLC examination .
So , depends upon the state ...find a easy or quick way to correct your birth certificate .
1)Apply for you correction in a appropriate place
2)fill the form correctly
3)pay the feed
4)it may be long process ..so you have to wait for a particular time period .

Thanks