Hmm I don't think a halter will give you proper control if your horse does descide to do something silly, being only 4 and all , even if you think she's calm. Maby a rope halter style bitless, but not your average halter.
I have a Dr Cook bitless bridle. I use it on my TB. Love it to bits too
Yea the price is high, but it turned me bitless after using it
Even my other horse is now bitless, altho he's in a hackamore not a Dr Cook one.
But yea , I found Foxy took to it pretty much straight away. I have jumped him in it, taken him on beach rides and have even had him go bucking and still been able to pull him up fine , so I don't feel any loss of control because there is no bit in his mouth
So yea I reccommend them.