This was still the era - it would end later in that famous decade - when to be young was a social encumbrance, a mark of irrelevance, a faintly embarrassing condition for which marriage was the beginning of a cure.
In Ian McEwan's "On Chesil Beach," the narrative captures a societal perspective where youth is viewed negatively. Young individuals often face social pressure and are perceived as burdens or less significant. This mindset suggests that immaturity is not a desirable state, and the transition into adulthood, often signified by marriage, is seen as a solution to these perceived shortcomings.
The quote reflects a specific historical context, indicating that the cultural norms of the time placed great emphasis on maturity and traditional milestones. The idea that marriage serves as a remedy for the awkwardness of youth highlights the constraints and expectations placed upon young people, which created a sense of urgency to conform to societal standards.