Reunion with sibling

Has anyone reunited with a sibling put up for adoption? I just learned I have a half sister out there and I’m struggling with my emotions and where to go from here. My Mom is giving me the feeling that she doesn’t want me to meet said sisiter yet but I don’t feel like she has the right to make that decision. We’re all adults, I’m 36 and my new sibling is 48. Any advice from someone experiencing this?