Linnet Purcell is small, blonde, twelve-and-a-half; a comer among the younger ranks at San Francisco's Dell' Axte Repertory Theatre; and a victim--she overhears, miserably--of ""terminal cuteness."" The book itself suffers from chronic cleverness, plus a mild case of the cutes; but it does bubble right along--meanwhile suggesting enough grown-up tensions to satisfy TV-conditioned kids. Hot-wise, the story is quickly told: Linnet has won the part of Peter Pan--but she's still tormented by worldlier, sexier Bayside School classmate Margaret, who's playing Wendy, and still ignored by her analyst father and naturalist mother, who are wrapped up in each other. So she cleaves to handsome actor-coach Whit and his current older love, actress Hilda--Mrs. Darling in the show. But something is going on, Margaret warns her; and Linnet eventually faces up to it: sneaky, nasty Hilda wants Linnet's part. Linnet explodes; director Zander rejoices at her ""passion""; she tells off her parents, stands up to Margaret, sees through Hilda's on-stage ruse, and plays Peter not perkily but ""wild and free."" Then, the performance over: ""Exit LINNET PURCELL (brisMy]: Still aged twelve and a half. Neither cute and perky nor wild and free. Small but growing."" Some of this is scripted, snappily, in scenes; some--like the last--is presented in the form of'stage directions. The rest is Linnet's narrative--a consistent, edged, amusing voice with presence if no emotional range.