It's probably her style, to keep from being disappointed, just assume one can't succeed then when one fails, it's not so bad. I look for problems (some think of it as negative) so I'll be prepared. But I don't think I'll fail or anything. I can see how assuming failure so one doesn't have to try in the first place (she's afraid) would work.

Good for you using your anger at her negativity to work to succeed at what you want.