I would think that this may very well be a possiblitly for you.

Of course, yes you would have to work on her re-call. Perhaps an obedience class first?

Any dog, especially one of her age should have her hips x-rayed to make sure her joints are healthy & stong enough to handle such intenese exercise. And of course a basic exam by your vet.

If all else fails you should be able to enroll her into the beginner agility class and even keep her in it just for the exersice, training & fun of it.

Have you spoken with your agility instructor about this at all? What have they said?
Maybe they can let you come in early with her one class or stay a little late to give her just a little experience with the course & see how she handles that.