You're a high-school sophomore who's moved to a new school. Should you hang out with the cool kids--or is that not your scene? What should you wear? What's more embarrassing: riding the bus to school or having Dad drive you? These are the choices you'll make reading "What If ... Everyone Knew Your Name," one of two "What If ... " books soon to be published by Random House. They're inspired by the popular'80s "Choose Your Own Adventure" series by R. A. Montgomery; his stories have been updated and return nationwide to bookstores this week. In July, Lean Forward Media is releasing a DVD, "Choose Your Own Adventure: The Abominable Snowman," with 11 possible plotlines. And next year, HarperCollins will sell an interactive adult novel called "Pretty Little Mistakes." "You can become rich and famous, but you can also end up joining a cult," says the book's editor, Alison Callahan. But not everyone's behind the pro-choice movement: last week net execs at CW passed on the Aaron Spelling show "Split Decision," about a 15-year-old who spends half her time as a misfit and half as a cheerleader. Hey, it's their choice.