Leemew...here is the things to think about when owning a draft horse. I own 2, my team of Percheron draft mares.
Hooves...I have come across many drafts who have crappy hooves. Read up on them, what is good, what isn't. Mine are prone to abscesses, just last night Smoke kicked out, the hoof pick went in the hole and I had blood all over the place. Partly due to bad genetics and bad farrier care prior to owning them, throw in the humidity and mud here...
Hay..again, depends on your area. I have 4 horses, 2 Quarter Horses besides the team. Our hay in VA goes anywhere from $4.50 to $7.00 for a 35 to 45lb square bale of good quality orchard or field grass hay. We go through, in a year, between 12 and 1300 bales of hay. If you have one, it will be quite a bit less money wise.
Farriers...depending on where you end up, many farriers will not work on a draft horse. People are lazy when it comes to teaching their animal to stand, give to pressure, leans, hold the hoof up and to ensure you have a good citizen that is pleasant to work with, you personally need to be able to work with that horse every day, even if it is for a few minutes. Run your hand down their let, pick the hoof up, give it to you, hold it up, etc...can you do this? I make our two lift their hooves for me while they are eating, holding them and if they go to jerk it away, I will growl at them or sharply say their name as I hold onto it till they again settle down. I am 44 so no spring chicken.
Emergencies...you need a vet who is up on draft care as because their metabolism is slower than a lighter horse, they need to be careful on anesthesia, how they work with them, they do not like to be man handled or roughly treated. Some are more prone to colic than others.
Saddles, harness, tack, etc...EVERYTHING is more expensive and harder to find when you have a draft horse. Are you in an area that you can get lessons to learn to drive? It isn't something that you can just do or learn from a book or just wing it. Can you ride? Do you have a place you can go for lessons if not?
Drafts can take advantage of someone if they are let to be pushy. You have to be firm with them and set boundaries. Also, draft horses take longer to cool down if you ride when it is hot and are worked.
And please don't take this wrong but...can you physically take care of a large horse? If there is an emergency and your waiting for the vet, can you walk that animal, sometimes up to a few hours if it is colic? Can you bend down to lift hooves or be on your knees doctoring wounds or anything else that may come up out of the blue? Slog through mud in the middle of winter or rainy season to throw hay, check water, things like that?
Just some things to think about. Not knowing how heavy you are, I can only tell you what I personally do. Oh, fencing too, they can be extremely hard on them.
Can they be ridden? Sure...