To be clear, neither is there any unified "Black" identity, any unified "Native American" identity, etc.

Identities are generally fluid and reflect matters of degrees of commonality and shared experience.

In your case, there are certainly some things you share in common with Germans, e.g. you share an Indo-European linguistic heritage which you don't share, for example, with someone who has Japanese heritage.

Of course that's simply an academic point -- you're free to feel whatever degree of identity affinity you like, which is what matters. Identity is constructed.