I just did something so stupid!!!

So earlier tonight I got to talking about the sisters I have from my biological father. I have never met them and don't know what brought the conversation up, but I looked him up only to find out he died the year I graduated high school...and I didnt know.  I feel like such a useless daughter, no he wasnt in my life, but i should have known!  So I decide to reach out to his other daughters, my sisters, but I am wondering if it is a mistake because the first thing that happened was she asked me what proof I had, well when I was born, they would not let mom put him on my birth certificate, stupid i know, but hey, in 1991 they tried to keep people from being bastard born, so they put down the man my mom had divorced.  She wants to meet sometime...but now I am hesitant because I dont want to be called a liar over something I am telling the truth about.  It kinda depresses me because I have always wanted to meet them, but now I dont know if they really want to meet me...