Matthew 20:2

And when he had agreed with the laborers for a shilling a day, he sent them into his vineyard.

The KJV uses "penny" instead of shilling for the coin. Inconsistency may appear in the fact that it is not always the young who take an attitude of "bargaining" with the Lord, so much work for so much pay. However, if our analogies be allowed, they were the ones who DID make that mistake here. Furthermore, the temptation to that very attitude is greater on the part of one who contemplates giving his whole life to God and who brings relative innocence and purity of youth to the vineyard. Conversely, the temptation is diminished in those who come later in life, scarred and broken by sin, and realizing their plight of unworthiness and hopelessness far more keenly than any young person could possibly realize it.