Q. How many of the "Head of the Class" class members are actually of high school age? Who is the oldest? - C.J., Philadelphia.
A. Only Tannis Vallely (Janice), who's 14, is a genuine high schooler. The oldest is Tony O'Dell (Alan) who recently confessed that he's 28. He doesn't like to admit it because, although he looks younger, he told TV Guide, "No matter how you look, when a producer asks you how old you are if you even say you're 23, they'll say, `Sorry, we're looking for an 18-year-old.' " Ages of the rest of the class range from 19 (Rain Pryor who's T.J. and Kimberly Russell, Sarah) to 25 (Dan Frischman, who's Arvid.)Q. What can you tell me about John Stamos of "Full House" and do you have an address for him? - C.B., River Rouge, Mich.
A. Stamos, born in Orange County, Calif., 25 years ago, started out as a rock drummer (he often sits in with the Beach Boys). He got his first acting role at his first audition, Blackie in "General Hospital." A five-day job stretched to two years before he left for prime-time series, "Dreams" in 1984. Since then he's done "You Again," made his feature debut in "Never Too Young to Die." Write: Lorimar Television, 10202 W. Washington Blvd., Culver City, CA 90232.