Congratulations Rainbow, I hope it all works out for you all...

I have an older brother that was adopted out, but I didn't know till I was 24 (11 years ago) when he came looking for my mum. It bought up so much stuff, stuff I'm still dealing with all this time later. He looked for mum because he had cancer and thought he was going to die so wanted to meet her before he did (he's in remission now). However, 'slow' is not in my mum's vocabulary and she drove him away with her desperate desire to play happy families and pretend he had always been with us - she rushed things basically, and there are feelings that although you may think you can anticipate, there are those you simply can not. So we lost him for another 8 years, not knowing if he survived his cancer or not. This was almost worse than not being told he existed in the first place (though I 'always knew'). He then found me on School Friends. We slowly built a relationship outside of mum so that if things failed with her again, I would still have my big brother in my life. We all learned from our first experience, and now my older brother (and his partner and 2 kids) are a part of all my family's lives. We were given a second chance and none of us are going to screw it up this time. Adoption affects an entire family, as I'm sure is obvious with your cousin, not just the adopted child and birth parents. Taking it slow is not just for your benefit, but also for those who you don't even know exist yet. You are not responsible for their issues, but taking it gently will certainly go a long way to positive processing and a happy outcome.
Best of luck, you are all in my prayers...
kp