Dangerous Ages by Rose Macaulay

Barry came down for weekends. He and Gerda had declared their affections towards one another even at the Looe infirmary, where Gerda had been conveyed from the scene of accident. It had been no moment then for anything more definite than statements of reciprocal emotion, which are always cheering in sickness. But when Gerda was better, well enough, in fact, to lie in the Windover conservatory, Barry came down from town and said, "When shall we get married?"

Then Gerda, who had had as yet no time or mind-energy to reflect on the probable, or rather certain, width of the gulf between the sociological theories of herself and Barry, opened her blue eyes wide and said "Married?"