Now It is not possible to change in date of birth after registration in 10th board but in some cases it might change in case of genuine clerical errors like in cbse board changes DOB within the year of the declaration of result and no request is taken after the year.your school can help you in this but its a long and tedious process its better to go with the dob whichever written on your board if there is no issue but if you still want to change apply for it in cbse regional offices you may change dob but only after their approval.