As another veteran horse person (over 30 years in various equestrian sports including racing & polo) take everyone's advice and get as much barn time as you can.
Horses are far more dangerous and delicate than they look. Learn about diseases, common leg injuries, conditioning to prevent injuries and all manner of what can hurt a horse or what a hurt horse looks like. Do you know what weeds in the pasture or leaves off what kind of tree can kill your horse? What do you know about colic or founder? What is mud fever? Do you let a hot horse drink? The answer isn't a simple yes or no. Do horses NEED shoes? If so why? What are the mechanics involved/affected in putting a shoe on a horse's hoof?
14 isn't old, but like any person: How is their conformation, life long nutrition and how have they used their bodies? Likewise, young horses can be worse if they were started too hard and too young or have conformation issues. Sometimes as a first horse, an older horse who's been there, done that is your best choice. But they won't put up with (nor should they) loping endlessly around trails for your amusement.
READ! READ! READ! Talk to people, go to horse shows and get an eye for conformation, learn about different breeds and their temperamental tendencies.
On the other hand, there are SO many opinions on what's good or bad on a horse. For example: We like BIG feet on a horse. There are people who like tiny dainty feet on a horse. We both have our opinions as to why...who is right? (I am, of course.
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But seriously, horses are among one of the most abused animals simply because people don't know or understand their physical and mental needs. Be a good horse person and learn before you subject a horse to mistakes you will make. And you will, it's how people learn.
I think everyone here has paid their dues and are more adept with a pitchfork than a pen. You owe it to your horse to be the best owner and to make sure, having a horse is an enjoyable experience, not a dangerous or tragic one.