You probably need to get an apostille, which is a certification by the country where your birth certificate was issued that the document is genuine. The apostille is governed by the Hague Convention Abolishing the Requirement of Legalisation for Foreign Public Documents.
I believe the EU has plans for an intra-EU system to simplify this sort of thing, which have not yet been put into place. I don't know, though, since all of my civil documents are from a non-EU country.
It's possible that, as gnasher729 suggests, you can just use a certified translation of your birth certificate. The way to find out is to ask the German authorities who need your birth certificate exactly what form it should take. If you need to get an apostille, they'll tell you. If you need to get a certified translation, they'll tell you. Babies are born to non-German parents quite frequently in Germany, probably every day. The workers at the civil registry will certainly know what to do.