Runaway (Sweet Valley High #21)

Jessica's had it with Sweet Valley.

Jessica Wakefield is sick and tired of taking second place to her twin sister, Elizabeth.  Everyone adores Elizabeth; she's kind and loving and generous.  But Jessica can't seem to do anything right.

Then Jessica meets handsome, sensitive Nicky Shepard, who feels the same way she does.  Nicky is running away to San Francisco and wants Jessica to join him.  At first she doesn't take him seriously.  But when things reach the breaking point at home, Jessica starts to see that she might be better off if she left Sweet Valley--forever!