R.L. Stine 
Dangerous Girls #2: The Taste of Night [EPUB ebook] 

Destiny Weller and her twin sister, Livvy, were as close as two sisters could beuntil Livvy chose to become a vampire, leaving Destiny behind. Now Destiny will do anything to bring Livvy back to the family. But in Livvy’s world of endless darkness, she knows there is only one way she and Destiny can be reunited Destiny must become a vampire too. . . . Which sister will live to see the glow of the next full moon? Whose lips will savor the taste of night? Who will survive? Ages 12+