I had a fabulous jumper who was also a red roan Appy... I think he wound up in a hunter/jumper barn's lesson string. (Actually, most Appies I know have been tidy jumpers)
I'm not judging this mare on her color at all... It is how she's built.
A really good jumper will usually be built at least level, if not uphill, their LS placement will be even with their hip or ahead of it, and they also usually have a bit more leg than this mare offers, from these photos I think she might have to really stretch to hit strides (not always though, especially if she is actually pony sized) the neckset will often be a bit higher (again, not always).
With that said though, most horses are capable of doing some pony club, I have seen some real trainwrecks doing their best to pack their kids around, they don't often do WELL... I'm not sure where you are in BC, but I am also in the province and I know there are some here that would be more likely candidates, and most you can talk owners down right now, in my own opinion of course.
My very first horse was a 14.3hh Appy mare, albeit one who was very different in conformation to this mare, who was able to extend enough to make her lines without coming too far on the forehand to clear her front end. I must say, my job was easier when we were allowed to use pony lines though (which was done in our lessons more often than not). We bumped along alright, but in hunters we never ribboned. (Jumper classes were a bit different and we did somewhat better)
So it isn't impossible, but then again... Why settle for a horse who doesn't quite meet your desire when the market will allow you to find something better suited for roughly the same money if you aren't in a real hurry?
I'm also not saying don't buy this mare... Just saying, I don't see the prospect your OP seemed to indicate you were looking for.