For our story about Abraham and Sarah having a baby in their old age (see Genesis 17-18 & 21), the kids acted it out. It’s a very simple story. I chose to read only excerpts from the story, cutting out the bits that were repetitive or not specifically about the coming baby.
All you need for props are a baby doll and blanket. If you have a couple of tunics for Abraham and Sarah, that’s a bonus, but not absolutely necessary.