About to be an Adoptive Mommy- Need some advise- New to here

Hello all, I am new to this site, and to adoption in general. I work with at risk youth so I am in constant exposure to adoptive children but have never had the first hand experience. Anyway, my husband and i are happily married and have been together for the last 6 yrs. He has two beautiful children from a previous marriage, but I have never had a child of my own. We had been trying for several years, and found out we are unable to have children. It has been very hard for us to accept this, but we finally did. Then, just a few days ago, on Thanksgiving Day, a relative of ours surprised us! She is a distant relative. Anyway, she is pregnant, still in her first trimester. Baby is due in late May or early June. She is very financially instable and is aware of this. She came to us concerned, and asking us if we would adopt her child. She is afraid if she were to try and raise it, she wouldn't be able to and that CPS may become involved because of the circumstances surrounding her and the baby's father's lifes. They are young, 22 yrs old, and trying to be responsible and do the right thing. Both of the birth parents assure us they are 100% in and will not change their minds, but I just have trouble trusting that. On Thursday, we have our very 1st OBGYN appointment. I am so excited, but so fearful that when she hears the heart beat things will change... We are so excited, but I have heard so many crazy things about adoptions. Does anyone have any advise on how we should handle this situation. We know we need a lawyer, but that's about all we know. I am so scared to get my heart attached to this sweet little baby. Could anyone please share advise on how you have handled your situations??