Can anyone tell me if I possibly still have anger issues

I'm 11 years old and when I was little I had terrible anger issues I get angry at almost anything and react badly eg: I was playing a game and my sister said I was losing so I screamed at her and slammed her head against the fridge btw that was the second time today in school I have people scared of me and losing friends coz of my anger can anyone tell me if a possibly still have anger issues and how to control it thanks