It’s hard, and a lot of people will say you have no chance at all. But honestly if you really want something you will make it happen. If it’s money because horses are HELLA exspensive you’ll make it possible. If it’s that you think you aren’t good enough, well if you really want it you’ll push yourself to be better. I think if you’re determined and want to be the best you can it can work out. But their will be a lot of sacrifices in your life to have such a thing.
Depends on your skill level, the horses and trainers you have available to you, your circumstances, etc. You possibly could, but it’s fairly hard and I don’t think it makes all that much money. You could try retraining horses though.