In family adoption

I just found out I was pregnant with an unplanned pregnancy from a one night stand and I’m considering my options. I’ve already talked to the dad and he is open to all options, but I want to let my sister adopt the baby. I was wondering if anyone has done this and what their experience was with it. I’m super close with my sister and she would be a great fit. She has been struggling with getting pregnant for 11years now and I want to give her that opportunity. I know I would make a great mother and I know I could do it if needed but something is really telling me I should consider this option. I’m just scared to get her excited and then I get scared and back out.