Inaccurate title:
The text says she “hopes”. There is nothing wrong with hoping.
The word "hopes" comes from the article writer, not Ginsberg. RBG used "think", a presumption, albeit one that admits it is an opinion.
From the article, the actual RBG quote: "My senior colleague, Justice John Paul Stevens, he stepped down when he was 90, so think I have about at least five more years,"