Younger sib won't let me read breaking dawn book sib has re-read it twice. fair or not? i take care of books.?

my younger sib won't let me read breaking dawn (which is a killer bc i'm dying 2 know what happens 2 edward & bella by reading) no spoilers or i will report. VERY sensative against spoilers. i've already gotten one... she asks how long it'll take me, i tell her she must ans. why she's asking this if i ans. her ques. she ignored me when i asked. she's re-read it twice already, and now she's working on a third or forth time. i'm very angry about this. it's pointless and unfair. so i just had 2 know what u people think.