What to realistically expect from a "reunion"

7 years ago my ex girlfriend from college contacted me with some news. She said I was a birth father of a 9 year old girl. This is the girl that was said to have died during a miscarriage, though I didn't know the gender at that point. I was engaged to my ex but we were both finishing college that year and our post college plans and realities ripped us apart. I remember the days we spent talking about baby names and looking at baby things in catalogs and all of a sudden noticing so many babies and toddlers out in public. At three months pregnant she called me and said she had miscarried and then broke up with me a few days later. She moved back to her hometown with her parents and I stayed to get my masters degree. 6 years later, at first, she told me she was adopted and left it at that. I thought she meant adopted by another woman and man. A year later she clarified that another man had adopted my daughter and they were married. I was furious and said some mean things at the heat of the moment and she broke contact with me for another year. Then I became obsessed with wanting to know more about my daughter and kept asking my ex for information and pictures. I was told that I was complicating things with their family and needed to leave her alone. Then a year later she said I could see my daughter. The reason was that my daughter knew about me the whole time and wanted to see me. My ex said closure was important for my daughter. I jumped at the chance but then changed my mind when I thought about it more. To me she was my daughter, but to her I was just some mystery guy that was painted as somebody not ready to be a father, not her "real father". I think I was just afraid of rejection, that feeling of seeing how real it was that I was not an important "real parent" like her "mom and dad". I'm not sure. All I know is I just couldn't do it. I was reading all these stories about people who meet their biological fathers for the first time out of curiosity and then want nothing to do with them and don't like them. None of it seemed fair to me. I was deeply hurt by it. I mean deeply deeply deeply hurt. Closure? I have written some letters but not mailed them. Just trying to explain myself to my daughter in case she ever wants to meet me when she is an adult I might give them to her. I read them over and over and feel like no matter what I say she will never understand why I feel the way I do and why I have not been able to get myself to meet her. I'm furious with my ex and she won't tell me what she is telling my daughter. I wasn't given a realistic chance to be her dad. I know to my daughter it looks like I abandoned her maybe. I don't know. She is a few years from being an adult, and I'm wanting to send her the letters or meet her. I'm not sure what to say, what to expect. How do I explain myself and feelings without coming across as trying to make her mom look bad? What's the reason for even meeting? Is it really closure? Is closure really possible? It's never going to be the way it could've been if I had been able to be a father to her.