I agree. I definitely remember things from before 7. Not many things, mostly flashes of images and textures of objects.
My earliest memory is a vague memory when I was in a crib. Based on certain specific details of that memory my parents place it to when I was around 2.
I remember vague details of the homes we lived in after I was 3 or 4, but not the first home we lived in at all.
Apparently I had a very bad fall at some point and put one of my new teeth through my lip and made a bloody mess everywhere. I have a scar there to this day, but don't remember the event in the least.
I remember my mother teaching me the alphabet with a foam alphabet mat [1] and how to tie my shoes when I was probably 3 or 4. I also remember the moment my mother taught me the difference between how to say "three" and "tree" and permanently corrected what would have been a difficult speech impediment.
I remember my Kindergarten teacher's name and my favorite toys from when I was 4 and 5.
But the number and quantity of my childhood memories explodes after I entered 1st grade at 6. I feel like I remember more about 1st and 2nd grade then I do about most of the rest of my elementary and middle school education combined. Some really detailed events even.
1 - http://www.lcevafoam.com/img/Product/FM-910.jpg