Well, that's a hard one. I found out my stepfather adopted me at a young age. I was 32 years old before I met my biological father and discovered I had a half brother and half sister. His wife wasn't too happy with my appearance. I tried to establish a rapport with my sister but she didn't seem interested. After a couple of attempts I let it drop. I'm just saying that you can friend her and she might be glad to hear from you but then again, she might not. If she seems indifferent to you, there's nothing you can do about it. BTW, I still haven't met my other brother. You have nothing to lose by making contact but be prepared for the possibility of rejection.