Hmm... I'm not going to take the same direction everyone else did. As far as you being able to pay for it, I live paycheck to paycheck. I'm 19, have two horses, pay rent, paying off a truck, and paying for my insurance. Not to mention any and all care my two horses need. But I do it. I may be making more than you are right now, but I also have more responsibilities as far as payments go. I don't want to say that it's going to work for you like it has for me, but I also don't want to say it won't work for you. If you are uncomfortable taking that chance, then don't do it. It is ultimately your decision.
And on a side note, is it possible to maybe not take as many lessons? Or to move this horse to a less expensive place?