It's a book about a teenage girl who meets an anonymous boy online. They become close and she happens to move to where he lives without telling him. She moves to the beach town with her dad (I think her mom died and was a surfer). She starts working at a museum with a boy she doesn't like but things start to click and she begins to wonder if he's the mystery online boy. She had never told him that she moved to his hometown. She wanted to figure out who he was before revealing herself.

Read this the summer of '72 in Santa Maria, California. It was a library book. A girl in a wheelchair and her older sister are shopping and the chair gets 2 flat tires. A young guy (ex-Army, I think) with a prosthetic leg helps them get home. He and the older sister date, but he steps on her foot as they dance. He plays wheelchair basketball, his chair tips and he's standing upright for a second, then face-plants and everyone laughs. I know this isn't much to go on, but it's all I've got.

I read it sometime in the early 70's. All I remember is that a girl is in science class and the teacher is talking about how certain breeds of chickens are gone because they've been cross-bred out of existence. The next day, a male student brings in cages filled with the birds that the teacher said were extinct. The girl is impressed by the boy and asks to see more.