If you are still at home.... I would let this be your parents decision.
1. THEY will be responcible financially for the horse. Sure you better help out with all the chorse etc. but let THEM decide whether the family can afford and take care of a horse. They should know the finances of the family better. 8)
2. YOU will be taking off after a while. Most likely before the said horse would be....well....dead.
All the mumbo jumbo of the horse care (cost, vet, feed, etc.) behind....I LOVE owning my own horse.
What about a lease? Short term, part ownership works really well for a lot of people that don't know if they have the next ...oh...25 years to take of a horse.