I learned when I was 4 that I was adopted. I was always told it was a closed adoption, with no information on my biological family.
When I was 13, I noticed my grandma had a picture on her wall of a young girl who looked like my twin, and everyone claimed not to remember who it was. At 17, I found out my adopted dad’s childhood friend was actually my biological grandma. It was her photo on the wall, and why it looked so much like me.