I found my daughter and I need your advice!

Whoo! This is probably going to end up being long... About 10 years ago I was told a rumor that I had conceived a child with a young lady in the town I went to high school in. Her birth mother was apparently unready for parenthood and gave the child up to her parents without telling me about it. I was skeptical, but was shown a picture that was pretty hard to deny. I immediately began trying to contact the birth mother. She denied the story, but wasn't as convincing as the picture. So I kept digging and eventually called a local government office that keeps adoption records. The lady I talked to probably wasn't supposed to read the adoption certificate to me, but she seemed to empathize with my plight. The certificate provided a handful of details that all but confirmed that I had a daughter. I tried to contact bmom a few more times, but was ignored. I eventually decided that I would lay off and avoid harassment charges involving a minor, but only until I came up with a better plan. If I couldn't come up with a better plan, I'd revisit the issue when she turned 18. Well, her 18th birthday just passed. I sent separate messages to bmom, amom and adad. (Am I using the adoptive/birth shorthand right? I just found this site and read a few posts and picked that up.) Anyway, all the messages were ignored. So, yesterday I went and knocked on their door. I talked to aDad, who was not pleased to see me, but wasn't particularly rude. He just seemed to feel like I didn't have any business there. A couple of things he said make me wonder about what version of the story he's been told. I sincerely hope he reads his dang Facebook messages! He pretty much stonewalled me, but then out jumps bMom! (Not really that surprising, it's her parents house after all.) She came outside and we smoked cigarettes and talked. She again denied that the girl was mine, but confirmed that she did have a child who her parents adopted and that the child still doesn't know she's adopted. She said that she knew for sure who the father was and it's not me. I told her that I was skeptical, but I didn't see any use in pressing the issue. On some level, I think she was trying to do me a favor to let me stop worrying about this. However, she's still a poor liar and when I reviewed the conversation later, I recognized a pretty big inconsistency in her story that makes me even more certain this is my daughter! I'm trying to keep this short and avoid giving out personal details, otherwise I'd explain these inconsistencies. So, what I'm here asking you guys for is advice on how to proceed. I feel strongly that I can be a positive influence on her life. I also feel strongly that it's going to break my heart and drive me crazy if I don't get to know her! But that's not as important as not burdening her. I'll be fine. It's worth noting that she has an aunt she's never met that has recently been diagnosed with brain problems. (Again, avoiding personal information.) Her aunt, my sister, is one of the coolest people I know and undoubtedly would be a good influence on her, but these brain problems will eventually probably kill her and might make her a very different person very soon. Like, I kinda thought I'd already lost the sister I knew, but she's doing a lot better. She's a little goofier and her memory is terrible, but it's still her. The point there is that there's some urgency to this situation. I know it's not ideal for her to find out this late, but it seems like it's better to find out sooner than later. I'm pretty sure she will eventually find out. In my digging, I've found five people that knew some portion of this story way before I ever got to them and this isn't a big town and these people aren't great at keeping their mouths shut. I think it's definitely less than ideal for me to contact her out of the blue and tell her. That could be devastating and could ruin her relationship with her aParents and spoil our relationship to be. But I think it's better for her to hear it from me than from some other idiot. I think the best thing would be for the aParents and bMom to tell her. She's been raised to believe that bMom is her sister, so they already have a relationship. Unfortunately, they don't seem to agree with me. I'm really hoping that aDad reads his Facebook messages and sees my compassionate, well articulated points and my version of the story that has the weight of the truth behind it. Maybe then we can at least get the ball rolling! So, what do you guys think? Should I give up? Am I wrong? I don't think so, but I figured I'd ask those questions first. If I do keep going (I will), what can I say to these people to get them to budge? If I can't get them to budge, do I contact her directly? If I do, how do I do it? I'm really optimistic that you guys have some insight on this, it's tough! Thanks for reading my novel.