Date problem in birth certificate

hi sir,

my name is sunil kashayp my query is regarding error in date of birth on my ssc certificate. Recently i observed there is mismatch of date of birth on my school ssc board certificate and 12th leaving certificate its a minor mistake but causing me major problems. My actual date of birth is 20-10-1988 where as on my ssc board certificate it is 20-9-1988 but on my leaving certificate of 12th and on my pan card, aadhar card, on my bank pass book everywhere  my date of birth is correct which is 20-10-1988. i have passed my ssc on march 2004, everywhere i used my mark sheet instead of board certificate i never used my board certificate anywhere that's why i wasn't aware of it i know its my mistake and i am accepting it but now i want to correct it, my father is not that much educated he didn't even submit my birth certificate in school not even he collected from thane muncipal office. I was born in thane current i don't have any proof related to my birth. pls guide me to resolve this problem.