Team Chasing and Showjumping require fitness and, personally I'd look for something larger than a welsh c cob type.
It'll depend on the pony or horse though.
I'd say you would be fine on anything from 14 to 15.2/16hhs. You need to consider the breed/type, health, conformation and fitness, especially if you're going to be doing those sports.
Some of our natives have round barrels and take up a lot of leg, however they can be short in front making you overly large on top, making it hard to balance. The narrower types will have your legs hanging low making it difficult to give aids.
Different sizes can cause discomfort for the rider as well.
Also consider that the saddle that fits your height and length of leg could be too long for a smaller pony's back creating pressure points.
Your weight might be an issue given what is required to team chase and jump even at lower levels. You're not asking it to go for a hack around the lanes at the walk for thirty minutes.
Go too large and you'll find youself over-horsed with similar issues such as balance and control, perhaps even frightening youself.
It's something you'll need to work out for yourself with support from your local school/instructor. Try as many ponies and horses as possible and see what you're comfortable riding and controlling.
Well, I'm 5'6" and weigh 10 pounds more (working on losing that as I switched to a plant-based diet since my lack of a gallbladder means I can't actually digest meat that well and it was affecting my weight). My Haflinger is 14.1, but is quite stout so he seems bigger (he also hasn't got any withers whatsoever, so that also affects his height).
I have long legs which contibute significantly to my height, and personally would not have felt comfortable on a 13.2 as a main horse. I did look at a 13.2 POA while horse shopping prior to buying my Haffie and he just didn't feel right I also happened to ride a 15.2 Azteca once and he was rather svelte so I also felt big on him somehow)
Im the same height and for me I wouldn't do anything smaller than 14hh and if they are less than 14.3 and don't have a lot of muscles I probably won't because of weight.
I would use height as a general rule though and if they are the lower end stick with the 20% rule.
You seem to be obsessed with your height and weight vs your horse/any horse. At the height you give and build you'd be top heavy for a 13.2. You have a Welsh Section C already and you've been given advice on this. You'd do better on something in the 14.2 to 15 hand range. I thought you also had a TB cross? What is keeping you from using that horse?
Welsh C’s are now bred for children and harness work, they’re sturdy but they’re also compact so shorter in the neck and back than some of the other British natives.
As an adult rider, you wouldn’t be able to compete in 13.2 jumping classes aimed at juniors so you’d be pushing the pony beyond its limits, not just in terms of the related distances and bigger spread but adding to the task by asking it to carry more weight and a top heavy rider.
I have had taller riders work 13.2 ponies but they all kept their weight at around or below the 112 pound mark
I wouldn’t even consider asking a 13.2 to carry your weight or height out Team Chasing. I did do a few with a Welsh D x Arab we had in the past but I’m 3 inches shorter and weighed about 112 pounds at the time. He was also incredibly scopey and a former JA jumping pony.