'two eldest sisters' does it a wrong expression?

[sweetpumpkin]

I read 'Beauty and the Beast' rewritten for beginners. I saw an expression 'the two eldest daughters' in the book. As you know, there are three daughters in the story. Can I generally call the first and second daughters among three daughters "the two eldest daughters"? How about 'the two elder sisters'? If both are right, which is the better expression?

[Mister Micawber]

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I think 'two elder sisters' is the logical choice.
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_________________
Canadian-American native speaker
who teaches English for a living at Mister Micawber's
ESL cafe: Interview with Mr. Micawber