Wrong birthday in different docs applying for passport

The fact is that you have attach the original birth certificate with the passport application.  If your date of birth differs from the birth certificate to that of the school certificate, you can attach an affidavit declaring the erroneous date quoted in the educational certificate and submit it, suppose the passport authorities are not convinced about the affidavit, you have to obtain a court order declaring the correct date of birth, consult a local lawyer and proceed.

file a suit to declare your correct date of birth and have the copy of the decree along with the application for passport. That will be the only remedy