Drat! You Copycat! — Nancy Krulik

Katie is an ordinary third-grader -- except for one very extraordinary problem! She accidentally wished on a shooting star to be anyone but herself. But what Katie soon learns is that wishes really do come true -- and in the strangest ways...

Becky, the new girl in class 3A, is a great big copycat! She copies everything Suzanne does. Suzanne can't stand Becky! Then the magic wind turns Katie into Becky. Will Suzanne change her mind about the new girl? Will Katie turn back into herself without causing too much trouble?