Welcome to the horse forum!
I'm not sure how much you know about horses, but I would HIGHLY recommend you take lessons for a while before you go and buy a horse. Horses are a huge responsibility and there is a lot of knowledge and skill that goes into riding and caring for a horse.
Lessons are a great way to gain knowledge and skill with horses. You would be learning under somebody who has a great deal of knowledge about horses. If once you have decided you are ready for horse ownership, mentally, physically, and
financially, then you should think about buying a horse.
Hope this helps!