Same as what Catriona and Sharon say. I often see ponies under 14hh jumping very large, but a huge horse wouldn’t be able to. It also depends on if they have any health issues that would be preventing them from going a certain height.
Hope this helps answer your question!
I agree with Catriona. Height does not determine how high the horse can jump.
It’s not about the height of the horse that determines how high they can jump it’s the horses ability and training. My 16.3 horse couldn’t go over 4 feet but my 15.2 can sour over 5 with ease. Different abilities, athletics, and the riders capability determine the height.