So in the beginning of the book her aunt (Mother grandmother? Can't remember but older female relative) dies from the heat while baking a turkey. The girl sneaks aboard a spaceship and is caught. She's paired up with a guy who she doesn't care for. The captain teaches her to play the piano. Halfway to the world they are to colonize they turn around and head back to earth for some reason. Discover that Earth is healing itself. The girl has fallen for the captain.
I think the cover was of a girl sitting cross legged on a piano that's floating in space. Read this back in 8th or 9th grade. So 1995 or older release into paperback.