Translation:I am her younger sister.
It's worth remembering that 彼女 is used both as a female pronoun in third person (her) and much more usually in my experience to mean girlfriend.
Ok, I mistook this as "she is my girlfriend's sister"
Would it be right if it was "Watashi no" instead of "Watashi wa"???
From my understanding
Imouto = younger sister
Onesan = older sister
I'm a bit confused now, in other answers it seemed that imouto can only refer to your own younger sister, but here it seems that it can also refer to yourself?
Yes, it can also refer to yourself. While older brother/sister have "in-group" and "out-group" versions (あに / あね and おにいさん / おねえさん, resp.), there is only one word for younger brother/sister (おとうと / いもうと), regardless of whose family you're talking about.
I'm her kid sister. This translation is accurate. But, not acceptable.
I'm her kid sister. This translation is accurate. But not acceptable.
I thought the "no" between "kanojyo" and "imouto" modifies them to say she is the little sister, not that I'm the little sister. I would get it if "ga" was used instead of "no."
"No" is basically a possessive in this situation, so just like with the English possessive, the noun before it "owns" the noun after it. Hence, SHE "owns" the SISTER (in this case you), or it is HER sister. わたしは ("I [+ topic particle]") means you're (as the speaker) the topic of the sentence and です means "it is", or "you are" something. Since かのじょの is a possessive here, you can't be her since you can't BE a possessive. Hence, you are what the possessive is attached to, the sister. You are her sister.
Sorry if this is hard to understand, I'm not a language teacher so I don't know how to make this easily understandable.
it is right to say 私は彼の妹です ? the other sentence should not be "i am an imouto" ?
Wow got it wrong for sisters instead of sister. That's just rude duolingua!
Since the sentence refers that the speaker is a girl, it would be helpful if the speaker can actually be a girl.