Somewhere deep, she probably started believing it the moment the glass broke.
It wasn’t until later that it became conscious. Maybe when she froze time around Warren’s mechanical doodad, or stopped the spider demon in mid-air.
There’s no way. She couldn’t have known Warren would be outside, or predicted that improbable trajectory. She wasn’t even watching. And, hello, abstinence! Even with her full attention and powers, it’d be arrogant to think she....
Years afterward, though, she would still awake in a cold sweat, lightning crackling between her fingers, thinking:
If only she’d been ready, she could have stopped the bullet.