Average Horses

Recently, there is a post on COTH forums asking what the average horse is capable of. With regard to eventing, the consensus is that the average horse can do Novice! I just want to do Tadpole/BN! Of course, my horses aren't very average. Trouble is having hock issues and refusing jumps (because she's a brat or because she's in pain? The verdict is, it started as 2, but now it's 1). Cotton is 24! That's awfully old to be starting to jump. Though I'm not sure what she has gone in her life. We bought her from a lesson barn with too many horses. They only had her for a few years, prior to that, she was a boarder's horse who went off to college.

In any case, I think I SHOULD be able to get either horse around the local Pony Club's Amoeba level (18", dressage + cross country). Trouble has been there three times, she's seen the scary Training level jump that is NEAR one of the Amoeba jumps, and she's seen the massive barrel construction that is the finale jump. And she'll put it a respectable dressage test. But, she may have some attitude and get me eliminated. Or dump me.

Cotton has less attitude. I COULD get her around a dressage test without getting eliminated. I mean, it's about having fun, right? Not winning? I don't care about winning, I just want to not get eliminated (though any ribbon would be nice...)

I do NOT want to take two horses. That's just TOO much going on for my tastes. So, which do I take?