Your lowest gear is way lower than the requirement for that ride. You have a 19 inch low gear, and they are requiring a 39 inch low gear, so you quality (if they are really going to be snobbish enough to check). But if you have a mountain bike that weighs more than a road bike, you may need lower gears than they mention. Or maybe you are such a good hill climber that you don't need anything that low.