This is a spin-off from another thread, on which someone expressed surprise that anyone would remember things from when they were 3 and said that these memories must have been "put there" by a parent.
Now my earliest reliable memory is of looking around our kitchen, at the underside of the sink (can still see the pattern now), then going outside to where my mother was milking our goat. The goat seemed huge to me, taller than I was. My mother had a big stomach and the sun was shining.
This combination of elements puts this memory at around 20 months of age. It's entirely visual. I have an earlier far more smell and feeling based memory that makes people think I'm barking, so I won't pollute this thread with it.
Just interested: what is your earliest memory?