Join Date: Aug 2009
Location: New South Wales, Australia
A young horse as a first horse is not a good idea. Horses are not "raised" like children or dogs or cats. They're not pets they're livestock. The family that "raises" them will be their herd of horses, not their owner. Their owner trains them, and perhaps a better way to look at horse ownership is almost like a work colleague.
Imagine you were new to a workplace, you'd want someone who has done it all before to show you what your job is. In the same way a new horse owner wants a horse that has already done everything before so that they can improve as a rider. They want to be able to make mistakes, and the horse still is safe and behaved.
Now imagine you turn up at a job, perhaps an office job, and you and another guy there and you're both new and neither of you know what to do. Without direction and support neither of you would know how to do your job. This is what a green broke but relatively untrained horse would be like. Neither of you would know what to do, both of you would make mistakes, and neither of you would be able to fix it.
And now imagine you turn up to work and you have no idea what the job is or what to do, and then your new coworker turns up and they can't even read, write or use a computer, hey they might not even speak much english, yet somehow you're meant to complete the job together. This is what having a yearling would be like. You'd want to say to the person, go back to school you have to learn these bare basics before we can even begin to work together, you can't even understand the job. This is what a yearling needs - a trainer or owner who is experienced enough to teach the young horse the job, the language, the aids etc.
The best first horse is one that already knows everything you need to do, and has done it all many times before. This doesn't have to be forever, after a year or two you might find yourself ready to move onto a more challenging horse, eventually maybe even a yearling but before you can teach a horse you have to learn.
As for size, look less for height and more for build. A sturdy 15hh Quarter Horse will be able to carry weight easier than a fine and flimsy 17hh Thoroughbred. Look at any of the stock breeds, Quarter Horse, Paint, Appalossa, or even crosses out to other breeds and look for a strong, solid horse with thick legs and a wide build. This width will take up your leg. Saying that, I'd be look probably 15.2 - 16hh in a solid frame. Taller could be okay, but still look for the right build, as taller horses are often not bred to carry weight.