A horse or a pony?

I think it depends on what you want to do, a small horse, maybe 14hh would be a good size for your first horse. As for breed, i'd go for something hearty such as QH, try to stay away from TB's- high maintenance. It also depends on the horse your form a bond with...

it makes me laugh when people say, stay away from tbs. very sterotypical. honestly the tbs ive worked with were more laid back then the qhs, and appys ive been around. it has alot to do with training...

I would go with leasing a horse.

It is slightly funny about the breed question. My brother has his first horse now. A 6 y/o dead broke TB. I would say look at each individual horse, and find one that fits with you in personality and has lots of experience. You want something calm, but you may not want a dead head. It's all up to you, your parents, and the experienced horse people you work with to find one.

and I definitely agree that there are no breeds to completely stay away from, as mentioned. I always hear bad things about TBs, but I have one and know several others and they're awesome, very sane horses. my guy used to be a lesson horse. and it goes the same for arabs, too. don't let people give you bad ideas about anhy breed. it may be smart to keep in mind that those breeds are more likely to be more spirited, but that definitely doesn't mean that they all are. just don't pay attention to breed for now, and look for a sane horse.
and again, definitely, definitely bring a trainer. can't stress that enough, it's always a good idea to bring a trainer.

A horse. You want something you'll grow into, not grow out of. =]

Which is continual, and the rider is a beginner.

There are ALWAYS exceptions. But the chances of finding a beginner safe, LOW MAINTENANCE, TB are MUCH lower than finding the same in a QH for example.

I hate it when people think you are bashing TB just because you mention they aren't USUALLY the best beginner horses. They are bred to be athletic, explosive, high-performing athletes - So most of them are.

I got my first horse when I was ten he was green and about 7 he threw me off the first time I rode him. But to this day I love him and he has made me an amazing rider. For you I would I go for a horse middle aged not a old horse you can only ride for 2 years. With some experience.