Thats not old! I trained my TWH at age 16 to do barrels and we beat my trainer and her 7 year old many times and she kept telling me he wont beable to he wont get it, but he was really good and loved it. He was my first horse and I was 10 when I tought him to barrel race. He did it for 2 years and I got my horse now. If he was still alive and I hadnt gave him back to my aunt I would still be gaming off of him until he couldnt or didnt want to.
Good luck with your horse.