Quickly, before things get out of hand, clarify your experience with horses and give us some background information. Otherwise, you will her "get a trainer before you get killed" and "green + green = black and blue" and you won't actually get the information you came here for.
Now, if you have a horse even BLUFFING about attacking you, it's serious. If that mare ever does that again, step HARD in her direction and scare her off. That's aggressive behavior and you need a professional to deal with that. It's very very dangerous.