Is 50 old enough to be Chief Justice?

When I heard of the nomination of Judge John G. Roberts Jr. for the Supreme Court I thought he was too young for a lifetime appointment. When the Constitution was written people did not live into their eighties but on rare occasions. Now President Bush has nominated Roberts for Chief Justice. This is very disturbing to me. How can a person of so few years possibly be qualified for such an important position? Roberts claimed today to "not have an agenda." The problem is we don't know very much about this person. He has only been a judge for a few years. Heck he has only been a lawyer since the Reagan administration. I think a constitutional amendment may be in order making a minimum age limit for the court. Traditional retirement age seems appropriate; a lifetime of experience would seem to be an invaluable resource for a position in government so vital to the American way of government.