A [prefix] at [infix] early [suffix] can't [whole] everything.
What is the logical statement when the gaps are filled?
This statement can be resolved as follows:
A MAN_ at _AN_ early _AGE can't MANAGE everything.
Here, MAN is the prefix, AN is the infix, and AGE is the suffix. The statement rather philosophically suggests that we enter this life with a lot of learning to do!
Slightly different alternative answer
A MAN at AN early DATE can't MANDATE everything.
The point being that it takes time and experience in order to provide authority to others.