Should I add a cob pony to my horses?

Hi, I am wondering if I should buy a cob pony? I have set my eyes on one, a beautiful 14.2, hh, with a pinto coat, I was wondering if I should buy it, he is going for $ 1500, but I was wondering if I should buy, I am about 5'6" and close to 145 pounds, would I be able to jump, ect with him or would I weigh it down?