How high I jump depends on the horse I'm riding at the time. I showed 4 ft when I was 14 on my trainer's horse... Then I schooled my warmblood 4' and showed her 3'3 when I was 15-18... In lessons I have jumped 4'6 because that was the caliber horse I was riding at the time... Currently everything on depends on the horses I have in training. My best jumper is a 13.1 pony who I school 3'6, after that I school my 15.2 horse 3', but he's only a coming 5 y/o Paint so I figure that's pretty good.
My boyfriend would like me to add that he has jumped 5'... On a 16.2 Percheron, in a western saddle, while pulling back on the reins with all his might as it rushed to the gate of the arena and jumped out. He holds it against me that he has jumped higher than me, but this goes to show, that the height of the highest jump a person has jumped doesn't say how good of a rider you are.
EDIT: He wants everyone to know that the lady watching all of this unfold said that he had good form in the air, despite the horn pushing into his gut.