What should I do my boyfriends Ex wants to Fight me? And truthfully I'm down for it!?

she has been harrassing me since she's found out who I was I've had to change my phone number so many tims it's ridiculous she was friends with all of his sisters which didn't bother me she was there first and they practically grew up together but she harrased me so much she played on my phone like every other day she would leave nasty voicemails she posted stuff about me on her myspace page calling me all kid of names and making threats and from the beginning I remaibed calm and showed class she continued to go crazy on me. And I could never understand why becase before I met him I didn't know of her. I fel she should have been mad at him and not me but she vented on me of course and I had had enough. One night me and my girls were riding around and whe we left the house we had bad intentions I'll be honest to make a long story short. I saw her car pulling out of his driveway followed by his sisters car. The sister pulled off down some street and I followed the ex my and my girls pour gasoline all over her car and through a lit napkin on her car and left....still she didn't have enough so I caught her on his street again me and my girls busted all of the windows out of her mothers new car mind you she no longer had one but I was past livid and fed up with this girl. He called me askin if I did it of ourse I said no and remained calm to make and even longer story short it couldnt be proved that I did it she had no evidence. And now she hates me and wants to fight and feel I'm the reason she's down. She lost a car her mothers windows were taken out I have her ex fiance and she hates me.....but she started pucking with me first and there's only so much a person can take you know....??