If you're unconfident (even if it's only sometimes) then I don't think this would be a good horse for you. I don't mean to sound rude, but this is a horse that could easily take advantage of an unconfident, beginner rider. It would be better for you to find a "been there done that" sort of horse that's older (probably around 13 or 14+) and is a school master. You need something you can build confidence on and I do not believe that this is a horse that will do that for you.
"Always be yourself. Unless you can be a unicorn. Then, always be a unicorn."