I just now read it and I have to say it's amazing. I love the idea. It depends how fast you want to go with the story. The next chapter you could talk about her friends convincing her to take a pregnancy test. You could either make her want to go ahead and tell Natsu about the child or you could make he wait a few chapters, until the baby bump is showing. If you make him wait, you could let him get upset at first from hiding the child, but eventually give and and help Lucy through the pregnancy. She could bring up options like adoption. You could also go either way with that. You could make Natsu want the baby and Lucy too right off the bat, or you could make them both give into the idea of adoption until they see the baby for the first time.
