I'm afraid of dogs.
Eventually I learned that dogs are not necessarily dangerous. With a few exceptions. Including when they are backed into a corner or think you are going to re-enact a previous attack.
So I was worrying about the wrong thing.
It's not how big the dog is at all.
Rather it's how cornered the dog feels. (Which is exactly why they're good household pets - not only loving to the family, but magificent at scaring off burglars.)