The quote from John Updike's "Rabbit Redux" suggests that by the age of thirty, many people have formed their paths and made significant life choices that are unlikely to change dramatically. It implies that after reaching this age, individuals often find themselves more entrenched in their habits and routines, making new experiences or achievements less likely. The idea is that by this point in life, a person’s direction is largely set.

Additionally, the quote emphasizes the accomplishments and experiences already achieved by an individual. It suggests that whatever they have done until this time will likely be expanded upon, reinforcing the notion that past actions and successes can lead to further opportunities and achievements. Overall, it reflects on the momentum built in early adulthood and the impact it has on future endeavors.