I too agree with CD. But I am also not one who believes in teaching babies only 'the basics' & then 'letting them just be horses & grow up'. Firstly i believe ALL horzes, regardless of age, should be allowed to 'just be horses' the vast majority of time. Doesnt mean you have to 'throw them out' to 'grow' or do nothing tho. I believe the more you do now/when young, the merrier. But it's what you do, the way you do it, the mindset of horse & handler... that causes it to be 'too much' or not.
Sounds like a lot of what you're doing is Work. And for intensive periods. I think about the single most important task of a young horse trainer is to teach the horse to ENJOY what people ask of it. To think of it as Play not Work. And part of that, esp with an animal with such a short attention span, is not 'drilling' them on 'exercises' but just doing things here & there, for a minute or less, in the course of... going for a walk or hanging out or something enjoyable. Make the 'lessons' just by the by, non events.
Firstly I'd not be lunging a youngster much at all or above a short trot(not that I lunge much anyway but esp not on immature joints...). It may be that she is sire, somethings 'out' or such, so I'd personally get a chiropractic vet to come check her out too.
I would be consistently asking her for 'basic' stuff like yielding in various ways, and accepting and rewarding her smallest 'tries', not asking for too much. I definitely wouldn't be just continuing to ask her to load in a trailer if she balks for eg, for many minutes at a time, let alone hours. Instead, I'd only ask her for what you think she WILL give you, towards that goal - even if it's only sticking her head in or such - and quit asking & reward her for that, get her thinking it's A Good Thing when she does that for you, before asking a little more. Aim to quit & reward her before she decides to quit trying/resist you. Build gradually on success and when you run into issues, take had a dozen steps back(trainingwise) and go again from there.
If/when the horse does quit/resist, I would NOT (generally) stop but continue with the 'pressure' and get her to do something towards what you want before you quit/reward. Make sure it doesn't work for her to say 'no I don't wanna'.
Almost regardless of reason(if they're reacting in defence that's different), if a horse charges or otherwise seriously threatens me, I'd come down on them like a ton of bricks! Make them seriously reticent to ever try that tactic again. If she even thinks this behaviour is worth a try, this is seriously dangerous, for your sake, for anyone else who deals with her, and ultimately for her sake, as a horse who has learned to aggression against humans will rarely be tolerated. So you need to shut this behaviour down yesterday!
If it's beyond you, either get a good trainer to deal with her & teach you too, or if you feel you can't keep her & she is already aggressive, perhaps you can give her away to a good trainer, but I wouldn't try to just pass her on to anyone - might be more humane to just put her down now, rather than have her passed around to others who can't deal, or end up at the sales.