To me, it really comes down to who attacked first. The age/size difference is irrelevant if it’s self defense. I'm thinking the same thing. It looks to me as if she came right at him with clenched fists, ready to slug him.
If men are going to be chivalrous and refrain from hitting women, it's incumbent on women never to use the men's chivalry against them.
Tell that to my little sister🤣. That was her favorite trick. Hit me then run and hide behind my mom and telling her I was trying to hit her for no reason.