"I have a Western saddle that fits the pony well
There you go. Save money and use a saddle that fits the pony as you learn what you like and dislike in riding.
I started English. Bought an extremely nervous horse, and switched to Australian saddles to help me stay alive. Eventually drifted into western riding in terms of using the reins, and from there into western riding. Just because a western saddle has a horn doesn't mean you don't use balance. And increasingly, there are western saddles without horns.
My Australian-style with an American horn:
Abetta saddle no horn:
Every western horse I've met can be direct reined with two hands if you want. All of mine are fine with it. I prefer one hand most of the time. More to the point, I prefer to use as little contact with the horse's mouth as possible, while English riding teaches constant contact as the normal. When a new rider goes out with us, I tell them my horses don't care what bit you use, as long as you use it seldom...
But you can ride a forward seat (similar to jumpers) in a western saddle. You can ride a dressage seat in a western saddle, and there is a growing sport called "western dressage" that does the tests using western tack. You can use two hands riding western.
Conversely, you can ride trails in a jump saddle or dressage saddle. And many horses are ridden English with one hand and neck reining. And most horses won't care if you mix & match:
So...Washington state, and you have a good western saddle that fits? Start western.