It sounds as if you bought a nice mare that you can get along with well.
One of the things that you will notice in endurance is that (with an occassional exception) you can't always tell the good ones by their appearance.
My very first ride, we were camped next to some very nice folks with an older truck, stock type trailer, tents - all pretty much like what I was using, by the way.
The guy's mare (sort of a plain-looking little thing) stood around sleeping in her pen most of the time except when she went out on trail. She was second and BC in the LD - she must have come alive somewhere out there.