Judo = SO will be all around safer and less likly injured in various sports and activities.( like falling off of tall horses.... Did you say you teach? whats that saying about those that cant do..... j/k...) The self defense is really irrelevant.
Ballet= a dancers legs and butt. < BF bites his finger owwww, in a good way... >
Now that is a dilemma. Any selfish, sane H, would put his vote in for the ballet. and a loving practical H would choose judo. damn ---where is that twix bar.