Correct, David. And the same goes for "Sie" (the polite form of address in German) and "Du" (the familiar form, and cognate to the lost-but-not-forgotten "thou" in English).

When in doubt, we native English speakers should always go for the polite form of address - better to be smiled at while addressing a child as "usted" than to be frowned upon while addressing a grandmotherly type as "tu."