Aggressive Behaviour?

So,Hi! I may not seem like a aggressive person.I don't mean aggressive like hitting or things like that.But when I'm with friends,I just speak more aggressively,act more aggressively...and I really don't like that.How can I manage it?I want to be more calm and "sweet".And maybe you know why I act this way?And,no.My parents never hit me,swear me and I have a balanced life.I'm a Gemini and I have a twin sister.But i don't like being compared to her,and i really don't like people saying that we are twins.I just can't stand this.It's like I have no personality.Anyways,thanks a lot and if you can answer than just post a comment.Thanks!