THE early bird catches its worm. For Ann Chan Wai-yan, the English Advanced-Level four As scorer, this is more than just an over-familiar idiom - it is the secret of her astonishing academic success. She earned A(1)s in History, Geography, Economics, Use of English [AS] and Chinese Language and Culture [AS]. The 19-year-old student of St Stephen's Girls' School said: ''I think my memorising powers are at their best in the morning because the quietness of the hour clears my mind. ''Instead of burning the midnight oil, I go to sleep before 11 pm and get up real early, usually at 5 am, and study for two or three hours.'' Some students may find commuting to school a time-consuming, even tedious business. But for Ann, who is lucky to live within walking distance of school, the task is an enjoyable ''nice morning stroll''. ''It saves me time which I can spend on study or extra-curricular activities.'' Her extra-curricular achievements virtually match her academic success. She is a member of the school volleyball team and school choir, editor of the school magazine, and also helps backstage in the school's drama activities. She served as assistant stage manager for the Joint School Music Play '93, and in the last few weeks she has been taking time off from her summer job to serve as deputy stage manager for the Cantonese drama, Dead Poets Society , which goes on stage tonight at the Hong Kong Arts Centre. But of all these activities, she loves volleyball the most. So much so that she gave up the clarinet, which she had been playing since Form One, to devote more time to her beloved sport. Ann believes a healthy life and consistent hard work are the recipe for good exam results. Then what about study pressure? ''I sensed the school and my family expected me to get good results, but they never said or did anything that put extra pressure on me. ''The pressure came from myself, because I didn't want to let them down.'' Principal Too So Kwok-chun admitted: ''We did expect Ann to get good A-Level results, because her school performance gave us a hint she would do us proud.'' Ann wants to study business administration at the Chinese University, and hopes to go on to a master's degree later. Her stockbroker-father inspired her to enter the business field which she thinks would suit her ''outgoing, easy-going'' personality. Two other students at St Stephen's who got excellent A-Level results were Chan She-man - English Literature A(2), Geography A(1) and History (A1), and Leung Nag-yan - Use of English A(1), Chinese Language and Culture A(2), and English Literature A(1).