It's physically impossible for a little girl like that to knock me out. I might get a small bruise but other than that I would be fine. Now if I hit her it'd be like emergency facial reconstruction surgery levels of bad. Women are so fragile. But I'm also an accomplished black belt and boxed in college. Then again, I do not believe I could ever bring myself to use my full power against the opposing sex, but even at low levels of effort I am capable of mortally wounding a lesser man through the having hard combat experience. Indeed, if I just grabbed her arm as she threw her punch I would easily be able to dislocate her shoulder, break her wrist, and/or redirect her entire body into the ground using her own momentum against her. It is a simple effort when you know where and how to pull, twist, and turn. It would also serve as a proper lesson for her about facing the consequences of any poor decisions you make, such as attempting to punch someone you do not know. That sort of barbarous behavior has no place in this day and age, and civility should prevail over violence, but it is also wise to be disciplined in delivering violence when it is necessary, hence why I have trained so diligently. I am most probably in the top percent of fighters on Earth, but that is something I don't believe anyone should have to find out about me the hard way. I believe that whatever issues we have we may work out in an agreeable manner, and so I would stop her punch and ask her why she is behaving that way. I would invite her to sit and together we would come to the heart of the problem and resolve it through words, as that is the way true champions fight.