[Vince, Pt. II]

You may be swaying me on Cat, GrantDawg. That being said...

Spoiler

Cat did not seem to start reacting with fear until she started losing people. A big theme for her later is calling others "children of summer," and although her "summer" ended when Ned went off to war, she didn't really experience it, outside of having to deal with Jon Snow. I always envisioned her fear beginning when she lost Ned.