[If Tris says that, it's probably true. He's spent all his time since his parents were sent away learning that Tristan is right. Always right. He always has Ariel's best interests in mind, because he cares about him. And Ariel believes that -- has always believed that, and never questioned him. But now something feels wrong, and he's not sure if it's just the fuzzy memory of a dream of tearing Tristan to shreds.]

...I'm old enough to decide for myself now, I think.