My earliest memory is at age three when my younger brother was born and my family came in from out of town to take care of my older brother and I so my parents could focus on the new baby. I assume that it was memorable because it was the most momentous day in life up until that point and because my younger brother has been a presence in my life ever since.
I am definitely not the same person as I was fifteen years ago when my younger brother was born. However, I remember certain parts of the memory like I'm looking in on it and others like I'm myself in the memory.