User blog comment:Hyperborean/"The House of Hades" – official expectations blog/@comment-122.167.38.137-20130627134534/@comment-6064271-20130627161559

It makes sense because she is the smartest one and being the daughter of Athena she knows the best strategies for war and stuff. Also remember Percy and Jason were fighting for the front seat of he table, which is basically saying that they were fighting for the leadership of the group and Annabeth came out of nowhere and sat on the chair and they let her signifying that she would be the elader of the group.