Just curious... But WHY do you want to longe her? I never longed either of my QH's. They did the same thing you're girl is doing. They didn't care about the whip and they didn't want to run circles for me.....I honestly never really needed to.
Mine never tried to knock me down though. Perhaps just basic manners and ground work would be better for now. She's just now coming 2 so she may not understand what you want from her.
I'd do lessons in the round pen with just the lead rope and whip as an extension of your hand and getting her to understand when you want her to move her feet. John Lyons has a technique that he calls ........uh....*brain fart*....Anyways, he gets the horse to move it's feet North, South, East and West...Then he practices take offs ( Moving) and landings (stopping where you want the horse to stop)
I've done this with my horses and it was great as bonding time. You'll goof up and laugh and then the horse will goof up. It did wonders for Twister's ground manners and pushy-ness.
I know sometimes that an almost 2 yo looks like a big girl...but don't forget to allow time for the horse's mind to catch up with it's body.
Hope I helped. If you want more info on the Lyon's thing, let me know, I'll go dig up my book.