Pamela F. Service’s Under Alien Stars

Service, Pamela F. Under Alien Stars.  New York:  Atheneum, 1990.
In a future that sounds much like now, an alien civilization has been occupying earth for the last decade or so.  The alternating focalizing characters are a human boy, Jason, and an alien girl, Aryl.  To begin with the observe each other with disgust–her maroon skins [...]