Muzammil anwaar

If you get an RFE, you will only have to send the required document (It will be mentioned in the RFE Notice) which document will be sent to USCIS.
If you receive a rejection notice, then you will have to fill out new application form with correct details, and start the process again.
 
Rejection --> New Application + Timeline Restarts 
RFE  --> Delay in processing (Normal time required to process K1 i129F Application + 90 Days due to RFE)
 
 

Hi Muzammil,  My wife just told me about your situation, Since i assumed based on your application timeline, you are in Pakistan..following are the document you will require to change or correct your date of birth on your birth record/certificate.    Birth Certificate of NADRA (with wrong date of birth) Matriculation Degree CNIC Father’s CNIC (not mandatory but just incase) Union council birth registration certificate (if require you must have it as well) If its issued by Nadra take it to any main or district nadra office (Not a Kiosk) some Union Council do it too ( if you have good contacts with them)    after you get your corrected birth certificate, make sure to get it attested from Ministry of Foreign Affairs Pakistan - Also from your local Notary and or Union Council    Now you USCIS application scenario,    if you got NOA1 per your timeline, heres a few things that you might come across   RFE - Request for Evidence (which is what i'm thinking), where you will require to submit your corrected DOB Cert.  Application Rejection - Due to records not matching (because of the form i129f application you filled will have your date of birth) hence USCIS will ask you to submit your application again from the scratch. "it might sound scary but its actually only due to records mismatch"  
Now this all may sound horrific, But honestly its all a process, As long as you fix your record and do as USCIS instructs you to with accurate and correct details your application will be approved i.a. 
 
       

You may also want to keep or obtain some evidence of the official birth record from the hospital to confirm the birth date, just in case. USCIS won't know which birth certificate to rely on as the correct date.

Get it fixed and keep it ready. USCIS will probably send you RFE

No just one is changed on birth certificate other all documents has same or original one. Its the local government clerical mistake. Now they will update it and provide us new birth certificate. But we are so worried because our documents in USCIS with old birth certificate. We couldn't focus on the date.It has issued first time in jan 2021 when we sent the visa application. Just 28 days date difference. 

Why do the 3 have different DOSs?

DOB should match, that is one indicator of your identity. You should get your IDs and Passport to match your date of birth.