Falling: It’s not if, it’s when!
I was brought up that falling off is inevitable, but you have to get back on barring obvious broken bones, unconsciousness or spurting blood…
As a kid we were taught to roll off a stationary wooden vaulting practice horse. And fell off live moving horses often.
As an adult I fall rarely. In face my last fall was the first in quite a few years an resulted in a torn rotator cuff which after 4 months still hurts a bit… oh yes, I got back on and schooled that horse right away, then slunk off to be sore later 
There are so many ways to fall off it’s impossible to say if falling in general means any one thing. There are some horses that can get any pro off reliably (see: national pro rodeo bronc riding) and there are some people so green a stumble at the walk means landing on your head (see: my husband)
For me and my baby horse right now it’s a learning experience: I learned not to trot the horse up a windy ridge in the spooky evening, he learned that bucking when you’re excited has consequences!