Horsey people please help me!!?

I loan a pony called troy who is 13.3 or 14 hh I love him more than anything. But my mum and dad are getting me a new pony. I don't know wheather to get a really good new pony to do british eventing with as your pony has to be 14hh to compete. I dont know weather I should buy troy even if it is to small for my competitions? PLEASE HELP! :(