First, those are the ages of those men at the signing of the Declaration of Independence.

The Constitution was not ratified until nearly 15 years later.

Second, none of the people you listed signed the Declaration.

The average age of the Declaration signers was 41; only 3 were younger than 30.

I am afraid you have an unreliable source. The Constitution was ratified by the states, not signed by delegates. At the time of ratification, the average age of the delegates was 42. James Madison, for example, was born in 1751 and was 36 years of age in 1787. Alexander Hamilton was born four years later and was 31 in 1787. There were only four delegates in their twenties.