The relevant Florida statute is Section 767.04. Here are but a few of the problems you face:
1. You knew a problem existed since you warned the neighbor's granddaughter "several times" about the issue. It seems you knew your dog might bite her, and even if that's not the case, a jury could believe it to be.
2. I doubt you had a "Bad Dog" sign--most stores don't sell them--yet the statute requires that exact wording.
3. You may have a comparative negligence defense, but that only reduces the amount of damages the girl can recover, not eliminate them.
4. You seem reluctant to notify your homeowner's insurance carrier. That's a bad move. You have insurance for a reason. Use it. Even if the insurance company drops you due to the claim, it still might protect you from this claim.
5. The fact that your dog is an inside dog is legally meaningless. A dog is a dog is a dog, and in Florida, if a person is legally on your property, you have almost strict liability for her damages. Has she ever visited your back yard? Have you let her play with the dog? Then your defense weakens accordingly if a jury believes she had implied consent to be on your property despite your warnings. Juries can believe almost anything they want when it comes to a case's facts.
Be glad you don't have an exotic animal such as a panther. Anything--and I mean anything--those creatures do to someone else is truly strict liability.
I have a very sweet 100+ pound Doberman that normally would not harm anyone who is not seeking to harm my family. When guests come over, I put him in a locked room, and I don't allow him near kids.
Why?
Because you can never predict what kids and stupid people will do to dogs that will trigger aggressive behavior. I once had a friend of my wife's stop over, and when my wife was out of the room, that person BIT our Doberman hard enough to make it cry out in pain. Had my dog bitten her, we would have been liable since she was lawfully on our property. A jury would have likely reduced her recovery, but we would still be responsible for some damages. I've never allowed that person to return to our house.
Call your insurance company today; otherwise, it will have a defense of material prejudice and may deny coverage.
