She'll tell him soon enough - tell him again that she's seen enough that this isn't terribly frightening to her. It is frightening, but not so much so that she can't simply bluff her way through it.

Poison is very good at bluffing.

"Not this much, but you were. You were scared about what you were going to become. What it would do to the people you cared about. And... angry that you had that much to lose. That people had accepted you even though you were kind of hard to get along with, and you were still cursed, and it was still going to happen." Not one to mince her words. She's sure that Carlisle knows he's difficult to befriend, in any case.

"But--" And here she pauses, pressing her lips together. "You didn't say anything about still knowing who you were when it happened."