The 1960s were a time of change. So is life when you are 16. That combination propels the movie “An Education,” set in London in 1961, and makes it an unforgettable coming-of-age story. Attractive, bright, 16-year-old Jenny is stifled by the tedium of adolescent routine; she can’t wait for adult life to begin. One rainy day her suburban existence is upended by the arrival of a much older suitor, David. Urbane and witty, David instantly charms Jenny and introduces her to a glittering new world of classical concerts, art auctions, smoky bars, and late-night suppers with his attractive friends. He replaces Jenny’s traditional education with his own more-dangerous version. Just as the family’s long-held dream of getting their brilliant daughter into Oxford has seemed within reach, Jenny is tempted by another kind of life. Will David be the making of Jenny, or her undoing?Every so often a performance comes along that is so captivating that it becomes an instant classic. Carey Mulligan’s enchanting performance as Jenny is one of them. Channeling the spirit of a young Holly Golightly, she makes Jenny’s character blossom on screen from a girl into a woman, and transforms herself from an actor into a star. Director Lone Scherfig’s complete understanding of Nick Hornby’s extraordinary script brings its many dimensions to vivid life.