assault & battery

I live in the state of Michigan and was in an altercation with my stepmother that started as a verbal assault which unfortunately ended in a physical assault. My stepmother punched me in the face first, which I then defended myself by hitting her back. She is now threatening an assault charge against me. Can she do this even though both parties got physical? I was told by a friend that as long as both parties assaulted each other, neither person could file charges. Is this true?

In a civil case...

Either party can sue the other in a civil case, such as, if medical damages were a result. Of course, this does not mean that they will be rewarded. If they were the offensive party during the altercation, then they should be liable. If you were totally defensive during the entire altercation and endured damages, then you may be able to be rewarded for your loss.

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I'm not an attorney, hence do not depend upon this advice.