PRINCE CHARLES of England turns 30 today, a shocking bit of news to those of us who remember the baby prince cooing in the arms of his mother, or toddling around Buckingham Palace - it seems like yesterday. His mother was queen four years before her 30th birthday. Fortunately, Charles has had more time to enjoy his princehood, and to ease past the decade of his 20s, without having to bow his head beneath the crown.

This is as it should be; for like a little learning, a monarch in his 20s (God save the queen, of course) is a dangerous thing. In one's 20s one thinks like a pre-Columbian.The world is flat; and on the 364th day of one's 29th year, the dragons of decrepitude will undoubtedly surface, flashing their dentures. It is only when one finally reaches one's 30s that one realizes what the new world of responsibility means, what vast possibilities - perhaps even happiness - lie at the coast of maturity.

Not that we would wish to foist the metaphor of the new world on the bonnie prince. He is not of our world, nor in truth does he seem to suffer from the failings of young people generally, having appeared, in the past few years especially, to be mature enough for anything, including a kingdom. He is moderate and gracious, which is more than can be said of Charles II. And he has good head on his shoulders, which is more than can be said of Charles I.

Long live him.