Like already stated, the Parelli games are in a specific order for a reason. Your barn owner was incorrect in telling you to move on to the Yo-Yo game......that basically set her up to fail. The games are all about respect and safety. Do them in order and you will see a difference.
You said she is "unpredictable"........to me that says you have what Parelli calls a right brained introvert. Meaning everything can be fine one moment and then you have an explosion on your hands the next.......or you could have an extreme left brained introvert, which means this horse is very dominant, pushy, lazy, sets ears back, etc. Sometimes people call this horse a "jerk." If you go to the Parelli website there is a Horsenality chart you can fill out for her so you will know which "kind" of Horsenality you have, and what strategies are needed for a successful play session.
You are more likely to be kicked by a left brained horse than a right brained horse. The reason is b/c the LB horses just suck you in lol. You need to be exremely aware of her body language at all times. Look for things that could indicate RB or LB behavior.
Right Brained behavior: eyes not blinking, seems frozen to the spot (right brained introvert), head up, tense muscles, ears tight or moving rapidly, snorting, tight lips, tight or "J'ed" tail, can't stand still (right brained extrovert), twitches or spooks in place, more rapid breathing, seems to "check out" or go introverted or catatonic, glazed over look etc. Also take note of the SPEED at which she kicks or strikes or rears.....is it FAST! or is it more thought out?
Left Brained behavior: relaxed lips and lips, eyes blinking, relaxed muscles, leg cocked, licking and chewing, ears attentive or relaxed, can stand still, doesn't seem bothered by a whole lot, etc.
Now there are extremes to the LB behavior like kicking, biting, striking, charging, coming at you with ears set back, etc. but you can also see these behaviors with RB horses as well. Sometimes a horse will charge at you, for example, because he is afraid and feels like the only choice he has is to fight in order to protect his dignity. It's all about being able to read the body language.
Like I said, go fill out the Horsenality chart on her. That will help you greatly.