Horses keep teens out of trouble. Teens will usually get in trundle because of boredom. If I have a horse, I will not have time to be bored, and get in trouble if I have a horse and tack to take care of,
Having a horse will improve my riding, and I take on the responsible that comes with owning/leasing/share boarding a horse. As well, I will be able to participate in horse shows, and learn some dressage in my free time.
Having a horse will also help me improve in the everyday tasks. The responsibilities that come with a horse can also apply to the responsibilities of having a pet dog, like making sure it has water to it being cared for things like thrush, and rain rot.
In conclusion, I should have a horse because it will keep me out of trouble, improve my riding, and build my responsibility. Although a horse costs a lot of money, I think these three things, and more, over ride the cost greatly.