You're not proper Striker series, book 1.

Winner of the Frances Lincoln 'Diverse Voices' Children's Book Award 2014 Karen thinks she's not proper white. Her dad is Pakistani and her mother is white Christian, and somehow she feels as if she doesn't quite fit in... anywhere. So she's made a choice: she's switching sides. Karen's going to convert to Islam to find her true identity. But Shamshad, her Hijab-wearing school mate, isn't making things easy for her. What's her deal, anyway?...