Looking for the title and author of a science fiction book that introduced the "starseed" concept.?

Society has fallen into decay and neighborhoods have been walled in for security. Services like police and fire must be paid for by the neighborhood. The protagonist is a female whose father goes missing one day on his way home from work. The neighborhood is torched by thugs and the girl strikes out with, I believe, a younger sibling. They are headed to the country, to a sort of commune.





Along the way, the protagonist picks up a group of followers. She comes up with the "starseed" idea: that it is their destiny to leave the Earth and populate the stars. That's about where the book ends.





What's it called, who wrote it, and are there sequels? The book was published before 1998.