Nice idea
You have started with a lovely introduction to the characters. I have enjoyed this. The notion of staying young and watching the people you “grew up” with leave was kind of saddening and it made me develop some strange sympathy towards Peter from the start. The story is dynamic, you move fast. However, maybe you should dwell more on some events, rather than just announcing that they happened and skipping them. Such as the „they flew away“ part – it deserves a description of their flight at least and the feelings that overwhelmed them during the flight. Similarly, the island they spent a few months on - it is just mentioned in one sentence. Maybe you should think of expanding this, describing their life on the beach, their everyday activities and feelings. It is a huge difference from their foster home, so a comparison should be made. And the „saying goodbye to Wendy“ part as well. You need more narratives, more descriptions, not only „this and that happened“. On the other hand, I love how you ended your chapter. I am curious to learn what happens and whether growing up turns out to be a mistake from Peter's perspective. This is a deep question and you have done well by ending your chapter with it, since it takes the reader back to the real world and makes them wonder and ask themselves the same question you have posed. I love this. Finally, I would suggest some editing. There aren't any big mistakes, but rereading your story would probably make you check your sentence structure.
Read the story now