C.he knows that sheila doesn't like fishing.
Step-by-step explanation:
In this story, the narrator was fourteen years old boy who had a crush on sheila but sheila did not like both water and fishing which the narrator loved both.
At the end of the story, sheila went with a guy named Eric and the narrator learned a lesson that is Be yourself and do what you love to do.
This was the reason why he didn't tell about fish to sheila.