Why does Marguerite have such a difficult time with Tommy Valdon's attentions?

When Maya receives a valentine from Tommy Valdon, a nice boy from the town, she reacts negatively, because her experience has led her to think that a male having interest in her is necessarily a bad thing. She shows the letter to her friend Louise, and Louise explains that it is a sign of affection, being asked to be a valentine; Maya tears the note up, and decides to have nothing to do with it. The next day, valentines from the class above are delivered, and are read aloud in front of the class. Tommy sends another one to Maya, saying that although he knows she tore up the note, he will still think of her as his valentine. Maya thinks this note is sweet and decides to be nice to him, but only manages to giggle when she sees him.