Penny Pollard's Diary (Penny Pollard #1) by Robin Klein

Penny Pollard hates: old people, Annette Smurton (who has her own horse), wearing dresses and doing homework. On a school excursion she meets someone just as rebellious as herself--Mrs Edith Bettany-- (nearly) eighty-one years old and a new friend for Penny.

This is Penny's diary.

(Illustrated by Ann James)