how can i learn to censor myself?

[buggywuggy33]

my sister is 13, im almost 16, my mom doesnt like me to swear, and i generally dont, only when i cant think of a strong enough word. So all day my sisters been acting like a real 'a'. so, i dont remember what she asked, but i was across the room and i answered her question 'stop being a 'b', maybe' so she heard it even though i barely even whispered it and then she came at me. she stomped and started attacking me but my dad yelled so she stopped right after she hit me. she's pretty big and while my muscles are more toned than her, she knows how to use them better.... she knows how to hurt people, i'm not sure why. while i very much think she deserves everything i say about/to her, id rather not end up hurt so how can i keep myself from at least expressing my opinion outloud? also, i have trouble getting over stuff like that too. i've been mad for 2 hours now because of it. how can i stop being angry about it? thanks