If you want an even lower headset (which I don't think you need, her headset looks fine to me) work on flexing from side to side.
I noticed your reins were very short. You shouldn't need that much contact with the bit. To think of it, that's probably why your horse's headset isn't where it used to.
I'd suggest doing one or two shows just showing in novice western pleasure classes to gain experience and confidence before you go all out :)
Courage doesn't always roar. Sometimes it's the voice at the end of the day that says "I'll try again tomorrow"...