I often hear these mistakes made by German speakers who are learning English.
They say: She’s a good friend from me.
This is totally understandable and everyone would know what you meant if you said this. However, it is not a correct sentence in English and is a mistranslation of the original sentence in German.
Correction: She’s a good friend of mine.
Further examples:
They are good friends of ours.
We are good friends of theirs.
Have fun learning English!
Louise