While it is only a misdemeanor, it is likely charged as a Battery or Assault upon a Household Member, due to the family relationship. It is more serious than other misdemeanors, because it also carries restrictions on firearm ownership. These cases also typically come with mandatory counseling.
When you go to the initial appearance, plea not guilty and request the appointment of an attorney, if you can't afford one.
You do have exposure to jail time, but with a first offense and no other convictions, it is likely that you would receive probation. However, given the other consequences, it would be far better to negotiate the case down, beat the charge, or otherwise,have it dismissed. Domestic violence is being taken very seriously by prosecutors, but in your situation, (self defense), it sounds as though you will be fine.
For now, don't make any further statements and follow the advice of your attorney. In the meantime, obey the no contact restrictions, if any are in place. Your attorney can seek to have the charges dismissed.