Beauty and the Teeth

I showed a shining young mother her 4½-year-old's lower incisor baby teeth were slightly mobile preparatory to their falling out in the next year or so.  She looked stricken,  even pained, that her baby would be so old already.  Can she remember that I knew her when she herself was newborn?  "It happens so fast," I told her, and I have not been able to get her look off my mind all evening.