Searching for SIbling

I posted some time ago, and don't recall other info I posted. I have found out as well that my birth mother, had a daughter in 1966, with my birth father. She was also relinquished through Catholic Charities. It is hard to imagine having a sister who is from the same mother and father. I was adopted into a family where I am the oldest of 3 brothers, and 2 sisters. Amazingly we all look alike, but to actually see what a blood sibling would look like is always on my mind.