If a kid repeatedly hits you for no apparent reason, would you hit back?

Lets say your aunt's bratty kid hits you for no apparant reason. This happened to me while I was in a car with this brat pinched me hard in my arm for NO reason (this made my arm sore for days) and I didn't do anything. I just ignored that brat. But when she started pinching my 1 year old sister for NO reason, I stepped in and told her not to pinch and hit her. Then she started to pinch and hit me. I told her to stop doing that but she wouldn't listen. So I took my baby sister and went away from her. I told my aunt about her bratty kid pinching my baby sister and me and my aunt hardly did anything about it. At most she just told her bratty kid "no hitting." And every time I would tell my aunt how her kid hitting me and my sister, she would just change the subject and not do anything. My aunt had to come to see my mom like everyday and she would bring her bratty kid with her. Whenever that brat is alone with my sister she starts pinching her hard (sometimes in front of my aunt, but she doesn't nothing). Sadly I wasn't there to prevent that kid from hurting my sister on a daily basis because I was at work during the whole day. But when I came back from work and saw that brat pinching my sister, I blocked that brat from hurting my sister and told her to stop. When she started to pinch and hit me, I had enough and hit her back (with equal force). Then she went to tell my aunt, and my aunt called me in a way as if her kid was a victim and that I just hit for no reason. I told her that her kid hit me and my sister first. If someone hits my baby sister and I, I am going to defend my sister and me from physical attacks no matter who does it. When her kid started hitting me at a store, I hit her back and said don't' hit me. When that kid complained to my aunt, I told her "what do you expect me to do, just stand and do nothing while your kid hits me repeatedly??" The brat started to exagerate how hard I hit her and was crying and whining in the store. Then my aunt said in a loud voice how I am 10-13 years older than her kid (I'm 22). And that kid just came up to me and hit me hard in my abs (in front of my aunt). And she has hit me several times in front of my aunt. I ignored her to avoid making a big scene (although my aunt and her bratty kid was already making a scene). Because of her brats constant misbehavior and crying/whining, we had to leave the mall and my aunt put her brat in my baby's sister's stroller and to took her out. My mom acts like she's oblivious to what's going on and doesn't do anything either. It's frustrating to have to put up with this kid's behavior. Whenever I am in the car with that brat she just hits and pinchs me. That bratty kid would frequently threaten me by raising her hand at me like she is about to hit me hard in order to make me fear her. I find it ridicuous to have to fear this brat since I am an adult. That brat is completely disrespectful towards me. My aunt did see this and told her kid that she saw her raising her hand at me. I even heard that brat telling my aunt to hit me, but my aunt said absolutely nothing. Seriously, this kid is unbelievable and embarring to be with. When I was at a wedding with my aunt and meeting with my future fiance's mother, that brat was constantly crying and misbehaving that it was difficult for me to have a conversation with my future mother-in-law. And when my future in-laws and I were at my relatives' home, that brat was deliberately picking her nose in front of everyone. Even when my aunt and my grandma told her to stop she doesn't listen. It was so embarring and I was so pissed off at that brat. She misbehaves at the worst times. It's hard to just ignore her when she does things like that. That brat has also tried to steal my personal belongings and would claim that it is hers. She has taken and ruined many of my makeup (for instance she broke my favorite lipstick by smearing all of it on my baby sister and messed up my expensive eyeshadow kits). Even when my aunt tells her brat not to touch and mess with my makeup and personal things, that brat doesn't listen and my aunt doesn't do anything else about it. I really don't know how to deal with this disrespectful, uncontrollable brat. It really pisses me off when she hurts my baby sister and trys to hurt me and threaten to hit me by raising her hand. What you would do if you were in my situation.