P.J. Halliwell

On the Show
Her mother saw her in visions a few times in the three or so years before her birth. In "Forever Charmed" P.J. is seen with her younger sister, Parker, and their baby sitter, Billie Jenkins, as their parents left to go to the hospital for the birth of their youngest sibling, a yet unknown baby sister.

In the Comics
Apparently, deciding that her mom shouldn't go back to work yet, Little Prue uses her powers for the first time to keep her mom inside, much to the obvious amusement of her dad, Coop

Little Prue protests her mom leaving her with her uncle, Leo, but doesn't keep Phoebe from leaving like she did previously. Presumably, she goes with Leo and her cousins to Magic School.

Little Prue gets to meet one of the people she's names for, Grams, and gets a new nickname from her. After all, what else would you call Prudence Johnna, but P.J..

P.J. gets a little loving attention from her mom when Phoebe comes home after protecting her boss, Elise Rothman, from Cal Greene.

Piper asked Phoebe how she got through this stage with P.J., indicating that P.J. was no longer beaming stuff at random.

P.J. gets to camp out in the front room with her older cousins, while the adults work on trying to get back Piper and Paige and stop Neena for good. When Grandpa Victor arrives, he gets to watch the kids, including P.J..

P.J.'s parents discussed how her dad never knew his family while Coop was holding her. Later, after her dad met part of his family, she went with her parents on a picnic where, unbeknownst to them, they are being watched by P.J.'s grandmother, Patty, and her mom's ex-husband, Cole Turner.

When Paige touched Prue and set off a change reaction of powers, P.J. is at magic school and beams herself onto a cabinet.

Trivia
Pat Shand said that P.J. was about two years four months at the time of Charmed Assault.