Finding Birth Family

I was born an hour outside of Moscow, Russia, and given up for adoption at birth. My birth mother wrote a statement saying she was a single mother, and had 3 other children and couldn't take care of me. She said she didn't hide the pregnancy. She gave a brief description of herself, the biological father, and then the names of my three siblings and their years of birth.I decided to search for them, first by mailing a handwritten (and translated) letter to the address my birth mother was living at 20 some odd years ago.I waited a month or two, but never heard back. I decided to search for my siblings, since they weren't much older then me, and probably used the internet. I was able to find all three of my siblings on a social media website, I introduced myself and began talking to them. They told me they knew about our birthmother giving me up for adoption, but wasn't told directly by her. They told me someone in their apartment complex told them about me, only a year or so ago. They told me my birth mother, and birth father are together, never married, but never spoke of my birth, adoption, etc. It was as if I never existed, and something totally swept under the rug.About 5 or 6 months have passed since I tried to make contact with my birth mother. In my letter, I didn't write many details, because when I sent it, I wasn't aware if it was her current address. One of my siblings told me she promised to respond when she spoke to her about me and how we all communicate.My main question is, how do Russian birth mothers/fathers handle the adopted child finding them? Do they usually not expect to be found? Was I overstepping my place?And, if my birth mother responds, how long does it usually take? Months? Years? Thanks!

I am not Russian, nor do I have experience with closed adoption. But I am a birth mother, who knows lots of other birth mothers. Sometimes the reason the adoption gets swept under the rug because of all the pain and shame associated with placing a child for adoption. I miss my birth daughter every day, and it hurts a lot. Some birth mothers choose to deal with it by repressing those feelings and not talking about it. I hope your birth mother responds to you, and I am so glad you found your siblings! Best of luck to you.