Harry Potter question?

Yes and No. First of all, James told Lily to 'take Harry and run' at which point she took him upstairs. Then James was killed. Then Voldemort went upstairs into Harry's room, where Lily threw herself across Harry. Therefore, when she was killed, he was shielded from seeing the actual event of her dying, and thought it was all a game. Therefore, her death didn't actually sink in properly, meaning Harry sees the Thestrals once he has physically seen Cedric die, and knows that it means he wont come back.