I know that you are not as big as me. Still I go into most situations at a disadvantage. That does not mean that I don't use every advantage at my disposal.
I agree that you were no win for use of force in the boys house. As an LEO I wouldn't shoot an 8 year old with a tire iron as I could disarm him without serious injury to myself, a firearm would be a completely differant matter.
The Mind set is extremely important in LE as is knowing that you are at a tactical disadvantage nearly every time.
Never relax even if you feel you have the situation under control things can change FAST.
The First rule I always try to instill in new LEOs is that it is easier to start low and build the force to meet the threat than to deescalate the force once its started, or to explain why you needed to use force on a angry but non violent suspect.