Hmmmm I don't know on this one. I was keen to get into the equine industry when I finished school, but soon realised there's not much money in it unless you are truly amazing and the best in your field. And even then it's a hard slog to earn anything unless you're in racing!
That is a lot of money for a one year horse husbandry course. I don't think I could justify doing that myself.
Have you looked into any university courses? I am doing environmental management, which gets me out doing a heap of field work. There are lots of agricultural and environmental courses now that are in demand with all this climate change and too many people around the world. Graduates are in high demand and you have an excellent chance of getting work at the end of it, plus a lot of the work is field based so it will get you out of the office.
I know the feeling of going straight from school into an office job. I was the same, I had a week from the end of year 12 exams to starting full time clerical work. Then I had a gap year before uni and worked THREE jobs, 2 clerical and one customer service. HATED it! Was glad to get to uni!
I think you need to think more about the future than now. Look hard into uni or even Tafe courses that you could get into, that would set you up for a well paying job that would allow room to expand and get promoted. The horse industry is a very tough one to get into if you want money.
If you go to uni, you can still have time to be riding, and working. I do it full time and have Hugo in full work, and also work on weekends, and keep my drawings business going. You may also be eligible for youth allowance which depending on your circumstances can be quite good money. Mine is certainly helping to pay for my horse and car!! Plus you certainly wouldn't need to sell your dog. Depends where your nearest uni is of course, but you can rent with a couple of students and live pretty cheaply while you get through it. Agist your horse nearby etc.
But yeah, I'd think very deeply about doing an equine husbandry course, even if people get scholarships from it... maybe look into how much they're earning, who employs them, and if they're employed at all!