If one can successfully transform the elixir and form an infant before the age of five hundred, they will have more time in the future to pursue higher realms.
It is known that although the higher a cultivator's level, the more longevity they have, for cultivators of higher order, longevity is never enough.
A Golden Core Stage cultivator may take one or two hundred years to cultivate to the peak of their current minor realm.
However, the time invested by a Nascent Soul Stage cultivator will be several times more.
Some cultivators, after successfully forming the infant, due to various factors, might take a thousand years to reach the peak of the Nascent Soul early stage.
In such a case, let's not mention whether they can break through the mid Nascent Soul stage barrier.
Even if they do break through to the mid Nascent Soul stage, the remaining longevity is simply not enough for them to attempt to reach a higher realm.