Agreed to fight cant back out now?

So im a girl and this other girl called me out to fight me...ive been in about 9 or 10 fights and ive won em all....but i just found out from a mutual friend that this girl is bringing a knife to tha fight! i done talked my **** and scheduled tha fight so now what? i cnt call the police cuz then she will come after me...this girl is hood trust me. If it was a fair fight id kick her *** but shes bringin weapons. and i dont want to bring a weapon cuz i dont fight like that i never want to fatally wound somebody and i dont want somebody fatally wounding me. But if i dont show up at all shes gunna call me scared...but F*** yeah im scared of a knife!