Older Sister, Big Sister, Elder Sister
The only woman in this city is your older sister. She's the only woman surrounded by a bunch of men, but she's following her dreams in the big city.
You want to go to the city someday, but you're not old enough yet, like your older sister is.
し
お, あね, ねえ
None
Your older sister may have moved to the city, but she kept her pet sheep (し) with her. Now the only woman in the city is your older sister, and the only sheep is her pet.
Picture your older sister and her sheep walking through the city. Everyone turns to stare at them, because they're the only ones of their kind.