Ah, Asuka had been training to fight in our world for a very long time, probably most of her life. [Shinji himself only had a very basic understanding of Asuka's life prior to arriving in Tokyo-3, though he did understand that she was selected as a pilot at a younger age than he had been.]

... She actually wasn't doing so well toward the end. [Is it really his place to tell Chika any of this? He keeps going, either way.] She was having a lot of problems actually doing anything in battle. Being here and being useful probably made her feel like she had a purpose again.