Perfect Girl by Mary Hogan

Out of the blue, Ruthie has fallen in love with the boy next door, Perry. He's suddenly grown up and made her heart go thwang, and Ruthie has no idea what to do about it.

Then a new girl shows up at school, and Ruthie realizes she has to do something, and fast. Jenna is perfect, from her perfectly straight hair to her perfectly manicured toes. Perry's noticed her, too, and worse, Jenna has noticed him right back. Ruthie knows she has to call her aunt, New York's "Goddess of Love." If Aunt Marty, romance columnist and woman of the world, can't turn Ruthie into a perfect girl, no one can . . . but she might also turn Ruthie's entire world upside down.