So I am thinking about getting this kid a horse. But I am not sure if they are really ready to have a horse and ride it.
He talks sometimes that he wants a horse and I can get him a horse, but when should I do this, how can I tell that he is ready?
I was horse crazy since I was old enough to read books about horses. Any child is old enough to ride (I got my own horse when I was sixteen, and taught my four year old sister to ride on my horse, my kids learned to ride when they were seven and eight) but in order to be old enough to be the primary caregiver for a horse a child must have a strong sense of responsibility, and he needs to have a lot of experience with caring for horses. I begged my father to let me have a horse all through elementary school, but it wasn't until high school that I was allowed to have one, and, looking back, that was a good thing. Until I was a middle teenager I wouldn't have had the maturity or strength of purpose to take care of a horse. I also didn't jump in "blind"; I spent several years riding and being in 4H before I knew enough about how to take care of a horse that I was able to do it myself.
There are a lot of rules that you have to know. Always wear boots. Not thongs or sandals and especially not bare feet. You can break the rule and get away with it, but not forever and sooner or later there will be broken toes. Horses bite and kick occasionally. They throw their heads up when they are startled, they rear, they shy. There will be injuries, of both horse and handler. Even if you are experienced these things happen and if you don't know what you are doing it is far worse.
"Having" a horse is not a simple matter. First you need a place to keep it. If you have property, you will not have the cost of boarding (which can run hundreds of dollars a month) but there will still be equipment, veterinary costs, etc. And while many children love the idea of riding horses, few are capable of the degree of work and time required to actually own one. Are you prepared to take up the slack? To spend 1-2 hours each day brushing, picking, shoveling up horse poo, feeding, etc? Or nagging your child because he is tired of working every day? Or you could pay someone hundreds of dollars every month to do it for you. And the horse itself costs plenty. Hundreds, if not thousands, of dollars. And finally, unless you really know horses you could get stuck with an animal which has behavioral or health problems that make it entirely a bad choice.
Here's what I would recommend. There are many stables that offer riding lessons. Give your son a couple of months of riding lessons for birthday or Christmas (makes a nice gift, I often find Groupons for half price riding lessons). If he is very enthusiastic you can arrange with the stables to add horse husbandry (taking care of the horse's needs) to be part of the lessons. Encourage him to get involved with 4H. If after all this, he decides that horses are nice but there are other things he'd rather be spending his time on, you have just saved yourself a boatload of money and annoyance. If he decides that he's just got to have one of his own (give a couple of years for the initial thrill to wear off), have a discussion between yourself and your son and his riding instructor, about the possibility. Often they will have stalls for rent, and they can help you find the right mount for your son.
Do start with lessons at a local riding school with appropriately sized ponies.
A kid can start riding as early as 2 years of age (when they can sit upright), but many places that offers lessons have requirements that are usually between 4 and 8 years of age for lessons.
When you go look for a place, look for a place that:
Older kids and young adults can care for a horse, to a bigger or lesser degree depending on their age.
Depending on maturity, I would say that around 8 or 10 they can start basic care. The main issue here is you need to make the commitment to go and take care of the horse every day, or at least most days. Kids can take care of basic things such as grooming, picking hoofs and possibly feeding and watering.
You will probably need an adult to help make decisions around fly control, clipping (either doing it or deciding when to pay someone to do it), blanketing, shoeing, getting correct tack, selecting and purchasing feed and supplements, making decisions and reminders around proper vet care (both emergency care and routine care, such as shots, deworming, dental care).
A small kid would probably be too young to effectively muck out, or clean up a pasture.
Older kids like teens can probably take care of most of these things, except maybe scheduling of routine vet care and making emergency decisions.
Note that many things in the 'horse care' can be paid for. If you have your horse at your own place, you need to arrange for the waste to be taken away, fix fences, repair boxes, everything. Most places you board take care of this. Many places also have options that will allow you to pay for things like grooming, holding for vet or farrier, even tacking up.
You have to be an adult to own a horse.
If you are the adult guardian of a person with a horse, you are in effect owning that horse, in the sense that you are financially and morally in charge of it's welfare. ( I believe this goes with any animal.)
While older teens can do most or all of the care of an horse, it is a big commitment, and there need to be an responsible adult.
If you are not ready for that commitment, then your child is not ready for horse.
*note: a select few races DO show ribs while well fed, but I have yet to see a pony race that does that.