This article is from the The Terminator FAQ, by Karsten A. Loepelmann firstname.lastname@example.org with numerous contributions by others.
Sarah realizes that the future is not predetermined; she can *change* the
future. (Remember Reese's words to her: "The future is not set. There is no
fate but what we make for ourselves.") The words show Sarah's rejection of
determinism; the future is not "carved in stone." The fact that the *words*
are carved is ironic.