Joseylovesrain123- size doesn't have anything to do with jumping ability I know 17 hand warmbloods who trip over crossrails and 12 hand ponys who jump 3'6". I have a friend who is 5'10" and she shows her 14.2 hand polish arab in 4 ft jumpers. Plus your horse is only 3 so he has quite a bit more growing and filling out to do. Good luck with him though I hope he jumps well.
As for everyone who is getting all worked up over weither aussie showjumper is telling the truth or not, just leave him alone. Critique the picture that is what the forum is suppossed to be for, and you're making yourselves look self riteous.
Aussie showjumper- you are jumping ahead and standing on your toes. Shorten your stirrups and sit up to the jump with your legs on the horse, let the horse close your angles don't lean up his neck.
Nice horse what are you asking for him?