I have tons of memories from 5 and earlier. My dad was in the Navy and we moved around a lot back then, so I can usually tell about how old my memories are by where we lived.
My earliest memory was in VA, and we moved from there when I was a year and a half. We had an apt. on the beach and I used to play in the sand a lot. I just remember my parents trying to get me get in the water one day. They wanted me to at least get my toes wet, but I was afraid a shark would come up and eat me, so I kept throwing a fit. (Jaws came out that year, so I was probably seeing commercials for it.) I was a very timid child! I believe this was when we were about to move, and I didn't see a beach again until I was almost 6.
For the next year we had an apt. in PA, and all I remember there was grey carpet and a sunken living room. I know I had to step up to the kitchen and hallway.
We then lived in a house in PA until I was almost 5, and I have a lot of memories there- too many to name. I remember dozens of things about the house, though I couldn't give you an exact layout. I have a feel for the backyard and neighborhood, and remember stoops with cement lions on the sides. I surprised my parents when I was 10 or so and realized I still remembered our phone number and address from there. (I don't now. I know the street name, but all the #'s are gone.)
My dad was then stationed in Bahrain for a year, and right after he left, my mom found out her dad just had a few months left, so we moved to her hometown in WV just before my 5th birthday and stayed for 1 year. I have even more memories there then in PA. It was such a memorable year. My mom doesn't drive so we used to walk everywhere, and I still remember how to get to Grandma's house, the store, school, my friend's house, etc. I remember a lot of people- some who were important to me and some who were acquaintances. I remember Miss Gowdy's class in kindergarten and all the caterpillers I would play with at recess. There are so many events that I remember vividly.
In some ways I tried to train my memory as a child. We didn't take a lot of pictures through the years, but I guess I still wanted to hold onto the memories after the moves, so I would reminisce a lot. By 7th grade, I was in my 8th school and probably my 12th or 13th home, so I would test myself to see if I could name all my former teachers, schools, addresses, etc.
I wonder how this relates to Anna. I know a lot depends on the person (my mom barely remembers anything from her childhood), but I think it's a good sign that I can remember so much after leaving these places and never seeing most of them again. I hadn't had such a traumatic event and had my whole identity stripped from me, so that would likely have a big impact. Even though I can recall some things that I never discussed my family, I have no reason to think they aren't real. I know they happened. That would be different for Anna, but even if she only remembers a fraction of it, that may be enough for her to search for answers.