My earliest memory is from when I was 3. I remember climbing up the stairs on the outside ledge, beyond the banister. I got to the top and my mother started freaking out because I could have easily fell. I think it was memorable because my mother was angry/scared and that left an inpression. I think I'm still the same person.
This actually reminds me of a distinct memory from my childhood. I was around that age, my mom was freaking out because I as at the top of the stairs, but instead of safely descending down the stairs and tumbled down and my mother raged.