Christina doesn't seem to have many secrets. For instance, when Will kisses her, the first thing Christina does is write a blog post about it. No, wait—the first thing she does is tell Tris. But the point is the same: Christina doesn't have secrets and she grew up in a place where there weren't lies and manipulation. That's either awesome or awkward or both all at once.

"It would wreck me" is a pretty strong statement. Like, if you imagine spilling your secrets, you might say "it would embarrass me" or "it would damage some of my friendships." But Tris rockets past anything like that and ends up with the word "wreck." She might be being a little melodramatic with that word, or maybe she thinks her secrets are really terrible things that would make people hate her. That's a problem with secrets: you don't know how people will react until you, you know, tell them.