Answer:
Percy Jackson was border patrol.
The the whole idea about this chapter is that Percy just wants to know how he could possibly be related to a god. And Annabeth tells him that his dad most likely is a god. She doesn't know which god, though. The only way Percy could have killed a Minotaur is if he had special powers that only a god could give him.
Explanation:
Sorry if it's wrong, I haven't read this book since 6th grade.
We need more evidence on chapter 1