Young wizards

1.

Thirteen-year-old Nita, tormented by a gang of bullies because she won't fight back, finds the help she needs in a library book on wizardry which guides her into another dimension.

3.

When a gifted little wizard begins experimenting with her new skills, her big sister and friend must save her from evil in this continuing fantasy series.
Young wizards Nita and Kit face their most terrifying challenge yet: Nita's little sister, Dairine. Not only is Dairine far too smart for a ten-year-old, she also recently has become a wizard, and worse yet, a wizard with almost limitless power. When Dairine's computerized wizard's manual...

5.

A novel “filled with very credible teen angst, morality, and an intriguing blend of science fiction and fantasy” from the author of A Wizard Abroad (School Library Journal).
 
Still recovering from an overly eventful vacation in Ireland, teenage wizard Nita Callahan is looking forward to some peace and quiet in her suburban New York home. Instead, her close friend Kit seems to...

7.

While Nita's sister and her dad host three young alien wizards, teenage wizards Nita and Kit travel halfway across the galaxy as part of an exchange program and find themselves again caught up in the dark doings of their nemesis, the Lone Power.

9.

Young wizards Kit Rodriguez and Nita Callahan manage to wangle their way onto an elite team sent to investigate the mysterious, long-sought "message in a bottle" that holds the first clues to the secrets of the ancient Martian race.