請教863211老師，Pijiang 老師關於 Petitioner documents

I am reading required documents to submit with my sister's DS-230 form.

Petitioner Documents
Applicants in the following visa categories are required to provide
1) an original or certified copy of their Petitioner’s birth certificate and 2) original or certified copy of their Petitioner’s marriage certificate from the Petitioner’s current and all previous marriages.

My question is that I only have one certified copy of my birth certificate left ( I had it on 1991 before I came to US), Can I just submit photocopy of original for my sister's application ? If not,wher can I get it certified in US ?

Thanks you vey much!!!