I knew I had fallen in love with Lolita forever; but I also knew she would not be forever Lolita. She would be thirteen on January 1. In two years or so she would cease being a nymphet and would turn into a "young girl," and then, into a "college girl"-that horror of horrors.
The quote reflects the narrator's deep, obsessive love for Lolita, recognizing that her youth is fleeting. The narrator is acutely aware of the inevitable changes that will come as Lolita matures, transforming from a youthful nymphet into an ordinary young woman. This transition fills him with dread, as he cherishes her current state and fears losing that unique quality he adores.
The emphasis on her age indicates a profound sense of...