All we know about Ella is that she’s a "remote and dreamy" schoolteacher who likes books (1.2.8). That’s all we know about her, and it’s really all we need to know. What matters is that, without even knowing it, she hooks Richard on books. After her interrupted bedtime story, he says, "I hungered for the sharp, frightening, breathtaking, almost painful excitement that the story had given me, and I vowed that as soon as I was old enough I would buy all the novels there were and read them" (1.2.37).
You have to admire his ambition. For the rest of his life, Richard and literature are inseparable. It’s also worth noting that she is Richard’s first crush. What other kind of girl would such a lonely, nerdy kid crush on?