I think it depends on what sort of lifestyle you want. Do you want to do pony club? Riding lessons? Adult riding groups?

I got my horse when I was 14, and we bought a second one a year later. Both fellas are still with us, both in their late 20's now. They live on 18 acres, have it to themselves and it's sufficent grass to sustain them (I think the ratio is one horse to 7 acres, otherwise you need to hand feed). They haven't been worked for a long time. I didn't do pony club or anything like that. We rode around home, around the area I lived. We had a couple of early vet bills, one for dermatitis (recurring) and the other for a leg injury (which was expensive - we had to do daily injections, four hours worth of stitching). They both happened when I was still a teen. The only other times the vet has visited has been in the last couple of years for colic.

Our horses weren't ridden on hard ground so we didn't put shoes on them, but had the farrier out to maintain their feet. Then there's the dentist and worming. We've had three rugs over the years for one boy, and two for the other. They have a habit of losing bibs. We've had the same gear since day one - my gorgeous second hand saddle is beautiful and soft. Looking after your gear makes it last. We used to give them hard feed when they were ridden frequently, but now they get some lucerne hay if the grass isn't of good quality and our vet advised us against making any changes to their diet at this point. Good luck, it's just the best thing, so much fun and huge reward. You'll end up with a great friend.