OP, he's a smart looking colt! With good feed and care you can maximize his height potential but even then he will probably still fall into the pony category when he's finished growing. Enjoy him nonetheless.
You can always measure from the hairline to the middle of the knee no matter what the age. It will be the same if he is 1 day old, or one year. Because oddly enough, the lower leg does not grow at all. And yes, if it is 14 inches he will be about 14 hands.