I, too, have to strongly agree with the others that this is not your amom's decision. You have every right to search and if her insecurity scares her, then let it be her issue. You are a grown women now. You have to do what is best for you.
While you are thinking about your amom, how about thinking about your bmom? The woman that gave you life and then placed you with this family. It was okay for your amom to take you then, knowing you came from another women, but now she doesn't want you to have anything to do with the women who created you. That is very selfish. She had 29 years with you. By reading many of these posts here, your bmom could be out there waiting for you, not wanting to disrupt your life. Have you read the posts here from bmom's who live many years in pain wondering about their child, if they are alive or dead. While not all bfamilies embrace their children they placed, I have to feel in my heart that the majority do. The posts you read here are the one's who have issue's and problems. Don't let all of them desuade you.
I really feel your amom is being extremely selfish and self centered. Thank God your bmom wasn't that way, or you wouldn't have had the life you have. Maybe it's time you think about her and what you need. Let you amom handle her own feelings. It's not your place to protect her. By sheltering her and allowing her to tell you what to do, you are allowing the fantasy to continue for her. You have two mothers, wheather she likes it or not!
I hope I haven't offended you. I, personally, believe in open adoptions, because I feel everyone needs to know their roots.
Hugs to you at this difficult time!
