I feel like the worst person in the world 😔

I am 37 weeks with a baby girl. I was stuck in an abusive relationship and he wanted us to get an abortion but I couldn’t because it was too late. I did not want an abortion but he was very controlling of me. So he made us go to an adoption agency and we did everything you’re supposed to do when you’re going to place your baby with another family. We picked out a really nice family. I didn’t want to give her to someone else. I have wanted to keep her from the start. Just last week, my aunt randomly moved back in town and she agreed to let me move in with her and she has a room for me and the baby. I found all this out this morning. So I hurried to get out of my boyfriends house so I could move my stuff to her house. I was so thankful to get away from him. But now I have to tell that family that I’m going to keep the baby and I don’t know how to do it. Can anyone offer advice? I feel so terrible. They were so excited. This would be their first 😥😔