Bridle is not necessary yet we start all of ours in a halter and rope. One less thing to worry about. You need to make sure you're confident so do whatever it takes. Also I'd ssuggest beig riding fit before you get on.
One she's happy cantering and jumping on the lunge make sure you can do lots of work standing on a block making odd noises / movements.
Remember she has to cope with 3 types of energy:
Environmental - what's happiness around you ( have a friend bang around gallop past etc)
Yours - of you stuff up and put too much energy in she must be able to cope ( random screams / jumps also purposely asking with too much energy better she flip out on the ground then on board)
Her own- if she does spook/ get riled up she needs to be able to calm herself down ( walk gallop walk etc online jumping) Posted via Mobile Device