I think you're wise to condition her to it ahead of time. There are some places, like we discussed in the other thread where Pitbulls must be muzzled when out in public. If you're ever visiting one of these places, your dog will already be comfortable wearing a muzzle. So, you're most certainly not setting her up to be DA. That's something that was selected for in the developing of this breed type. Of course, she may never exhibit any of that. But I think it's a great idea....just like it's a good idea to condition a puppy to a crate, even if you never will need one at home, the dog may need to travel in one or stay in something small like that while at a vet's office. Conditioning and socializing a dog to many, many things is never a bad idea. And being prepared, keeping it in mind is a good idea when owning a breed of dog that tends toward DA. I would never get a Pitbull and not have that on my mind to some degree. I didn't get my Doberman without having that in mind. They too, tend toward DA.
I conditioned my Doberman to wearing a muzzle. He never wound up wearing one except for one time when out and about. I put it near his face and fed him through the hole, (high value food bits) made a fuss and put the thing away for a while. Then took it out and did that again, putting it closer and kind of on, but not buckled...just for a couple seconds, good treats, praise, then done. Later on, did all that, feeding HIGH value treats through it, attached the buckle, but only for a second or two, then took it off....told the dog how wonderful he was and tried it again....adding gradually a little more duration. And just went from there...changing locations in the house, then outside etc before using it in real life situations. Well, you get the picture...all very gradual with lots of reinforcement for every baby step. (tasty treats, praise, a party after the session with games and more treats)