Don't waste your time. If you want to ride, have fun, and learn, get a horse that is broke. Green riders should never have green horses. The romantic idea of having a horse to grow up with is not a good idea in most situations. My parents had no horse experience, my mother was afraid of them, and my dad, a dairy farmer, thought of them as hay burners and treated them like cows. I got my first horse, a three year old, hardly broke and one who acted like a stud and had the attention span of a goldfish.
In my experience, you end up with more emotional and physical scars in the long run than just going out and buying some old guy who can take you places and moving up when he retires. I still have that gelding, and I still physically shake at the thought of riding him. He's gotten a lot better, but you'll never be able to ride with the same confidence. I've gotten a lot better, too, and have braved plenty of greenies since then, but I have more experience now to do so. I know some day he'll be an amazing horse, but instead of him being at his peak at 5, he sat out in pasture because I was too afraid to ride him. I can get on another horse I've just met and ride with confidence, but with him I just can't unless I'm in the right frame of mind.
I'm not a very weak person, but that trauma that early in your riding 'career' can shake you in a way that not many will even try to understand. I was cantering in my lessons before that, and after being thrown of a bundle of times, I had to relearn my gaits from a walk. I'm JUST starting to canter again, and this was years ago that it happened. I didn't mean to give you a novel, but a green horse can effect you in more ways than you realize should something go wrong. Even if it all goes right, if you don't know where to start, you likely shouldn't play the guessing game. I remember asking the same questions, and getting these answers, but after I few swift kicks the the butt I'm better for it, but I would love have been working on my riding skills and to think where I could have been.