Not a sound from the pavement

This week's stack of library books included Arthur & George. On the train in to work this morning, the first chapter introduced me to both the gentlemen.

One of the things which came up in George's description is that he doesn't have a particular memory that he regards as "his first memory", and had never considered that he ought, or that it was normal, to have such a thing.

( I don't either )

Do you have an earliest memory? If so, how old were you when it was formed? How can you be sure it's the earliest?