Answer:
Because she is the eldest sister according to paragraphs 9-11
Step-by-step explanation:
“I’m to tell,” said Isabel, “because I’m the eldest. And you two can join in after. But I’m to tell first.” There was nothing to answer. Isabel was bossy, but she was always right, and Lottie and Kezia knew too well the powers that went with being eldest. They brushed through the thick buttercups at the road edge and said nothing. “And I’m to choose who’s to come and see it first. Mother said I might.”