Climax of the story

Climax is when there's a big turning point.

I think the biggest turning point happens when Ender fights and he thinks that it's his last command from his school but later he finds out that actually there is third invasion.

I think this is the biggest turning point because Ender's like so comforted because he thinks he will never do this again but, suddenly he heards the news that he should fight again so I think this is the biggest turning point for this story and also for Ender