"I am not an artist yet."
Translation:Jeszcze nie jestem artystką.
Is it possible to have the adverb at the end in this sentence (and generally in sentences including adverbs of frequency)?
It might be possible, but it’s much more natural to put it in the beginning.
Why are both artystką and artystą interchangeable? Is it male/feminine?
Yes, or rather the other way round: "arystką" (artystka) is feminine, "artystą (artysta) is masculine.
It doesn't really sound good. It sounds mostly better if you put 'jeszcze' at the beginning of a sentence, but I'm not sure, as I'm not Polish...
I know this has been discussed before, but I am not understanding it. Why is artist instrumental and not genitive (because of the negative)?