I remember my 2nd birthday fairly well, and I possibly have one memory earlier, though it's hard to confirm. If it is a real memory it would be from when I was about 18 months old. I'm inclined to think it was real because, unlike other early memories that could be influenced by photographs, this memory is of a baby trike on a stone patio that was in an apartment complex we lived in when I was an infant, and of which we have no photos. I remember sitting next to the trike, and having somehow injured my arm or finger, I can't really remember which -- I just recall staring at the blood, which had formed a perfect little crimson bead on my skin.
Everything after age 4 is fairly clear for me, but I have a few large gaps around puberty and some from college, which I think may be the result of trauma.