How many years difference is there between you and your older sister?
What's the difference in age between you and your big sister?
ーHow many years difference is there between you and your older sister?
「あなたとあなたのお姉さんの間には何歳の違いがありますか?」=「貴方と貴方のお姉さんはどのぐらい歳が離れていますか?」
how many years difference is there between A and B? を使った言い方です。
older sister で「姉」
ーWhat's the difference in age between you and your big sister?
「あなたとあなたのお姉さんの間の年の違いはなんですか?」=「貴方と貴方のお姉さんはどのぐらい歳が離れていますか?」
what's the difference in age between A and B? のようにも言えます。
big sister で「姉」
ご参考まで!