Today I got into an argument with my older brother about something that I felt bad about so I tried to lock myself in my room but I could still hear him through my door so after a few seconds I ran out at him and he hit me on the left side of my head and I just said, "Are we really going to do this today?" It reminded me of one time over the last summer where I got mad enough and punched him in the face and broke his nose. I kept walking towards him without throwing a punch and used some wrestling moves to put him on the ground without hurting him very much and told h after a while that I was going to let him yp, hoping that he would call down but knowing full well that he wouldn't and after I let him up hit hit my in the head again before I pushed h away and locked myself in my room again, this time putting in earbuds so I couldn't hear him. I'm about two inches taller him and stronger, as well as much better at wrestling but I just can't hit him for some reason. Wth? I have plenty of reason and I'm not scared of him but I just couldn't make myself do it. I wouldn't consider myself "soft" either because I've qualified for state tournaments and am going to be the captain of 3 different sports, including wrestling. I'm not really looking for encouragement to hit him, but it's just driving me crazy that I can't. I'm 16 and my brother is 18. Thanks for the help.
Edit: forgot to mention that I enjoy playing action/fighting/shooting games so I'm not scared of violence or anything