My earliest memories are from when I was around age 3 or 4. It's less that I have one distinct memory that I can trace as being the oldest, and more that I have a jumble of memories from that same time period. I moved into a new house when I was 4 years old, so it's easy to place everything that happened in my old house as being a very early memory. One specific memory that stands out to me is of me breaking the rules by going into my younger brother's room and messing everything up. He is two years younger than me, so he was probably around 2 and I was 4. He did something to make me angry and as revenge, I decided that I would go into his room and take all of his toys out of his toybox. My parents realized what had happened and immediately asked me if I had made the mess. I denied involvement, but I'm sure that they knew of my guilt because my brother had been downstairs and I was the only other person in the house. I guess that the extraordinary circumstance that makes this stand out is the fact that I was getting in trouble and felt angry and guilty, wheras normally I followed the rules very exactly. I am definitely a different person now and would never think of ruining someone else's hard work for my own revenge, but I can kind of look back on my little-kid motives and understand and laugh at myself.
I also seem to have a collage of memories rather than one specific memory that I can trace as being the oldest.
I think this might be the case because as Ken was saying, we learn the most when we are young and especially once we begin to be conscious that we are growing we must become overwhelmed with new information.
Since we can't really distinguish time at that point, simply learn new things each and everyday our experiences and memories fromt his young age fail to have a distinct timeline since that had not really been established in our minds yet.