Wharton has employed the technique of changing first person pov to third immediately after an "Introduction" by the narrator and switching to the basic "here’s the story I found out…" to begin Chapter one with a younger Ethan Frome, the man who intrigues her/him in the opening. Here we meet she who intrigues young Ethan:
The face she lifted to her dancers was the same which, when she saw him, always looked like a window that has caught the sunset. He even noticed two or three gestures which, in his fatuity, he had thought she kept for him; a way of throwing her head back when she was amused, as if to taste her laugh before she let it out, and a trick of sinking her lids slowly when anything charmed or moved her. (p. 34)
Very nice simile–"a window that has caught the sunset." What Wharton gives us is both a feel for Ethan, as he watches Mattie, his wife’s young cousin who has come to help out, and for the woman herself. You can see him falling in love. You can see her confident, fun-loving nature.
You can see the trouble ahead.
The Lost Children: A Charity Anthology