There was a situation at my school with a counselor that me and my friends got into. I have to write a letter to my principal and was wondering if any one could give me advice on what to write.

This is what I have so far:

Mrs. XXXX

I am sorry for any part that I took in the situation. I know we shouldn't have been yelling anything in the first place. But I should have never been saying anything either with them. If you can please tell the counselor that I am sorry for any misunderstanding, I would really appreciate it.
I would like to sincerely apologise for my actions on [date]. I did not mean to cause offence (or upset anyone) and I regret that my actions had such an effect. I apologise and can assure you that nothing similar will happen again. What I did was wrong and I should have just walked away when everything started.

I would really appreicate it if any one could give me advice on anything else I could write.

Thanks so much in advance.