Riding with cracked ribs is painful, even with a rib bandage on. Don't ask me how I know this.
The real questions are how bad do you want to ride and how high is your pain tolerance?
The risk of riding with a cracked rib is that is you fall again before it's healed, you risk displacing the fracture and possibly puncturing a lung.
I think two weeks is a good recommendation.
Yes, learning an emergency dismount is a good idea. Beginners usually learn to do one at a walk and trot within the first 20 lessons, intermediates should learn to one at the canter. One learned, they should be practiced periodically.