Is it normal - memory blocking

When I was 12 years-old my quality of life was less than admirable. My family went through an eviction, my mother was working multiple jobs and attending college again, added onto this was the fact that my sister is severely disabled which made life more complicated and hectic.

We went to live with my brother's apartment with his wife and my mother and her completely lacked chemistry and frequently argued, which was distressful for everyone. Since I was very young, I usually observed rather than interfered which unknowingly to me made me depressed. I saw and understood how stressed my mother was but was too young to relieve any of the burden from her and at time felt responsible for some of the difficulties.

I was at the time, completely unaware of how much it was affecting me until many years later after we moved out, and relations with everyone in our family were fantastic. My sister-in-law (the one my mother didn't get along with) and I were driving towards her and my brother's new home when we passed the apartment complex that we used to live in along the way. She made a comment about the past and I gave her a strange look, becoming skeptical that we'd ever lived there.

She looked at me like I grew another head (maybe I did!). But as I continued starting at the apartments, I couldn't remember a single thing about them. They didn't look familiar and when she tried reminding me of the things that had happened there, my memory for that subject was lacking as well.

I was the first time I really noticed how I tend to block memories and experiences whenever I find them emotionally overwhelming. So, I was wondering... is this normal? Is it normal for your brain to forget something, even if it's supposed to be fresh in your memory because it was too stressful?