Is it filed as a Class C or Class A misdemeanor? Class C is an offensive touching and it is prosecuted in municipal or JP court; Class A is a bodily injury (it hurt) and it is prosecuted in county criminal court.
You will not need an attorney at the first setting, but I STRONGLY suggest you get an attorney to represent you. Regardless of the level of the current charge, if you are convicted or even if you get a deferred adjudication probation, then if you are charged with this offense in the future, it is automatically a felony regardless of the level it would have been. Moreover, even if you get a deferred, you cannot seal the case after completion of the probation.
This is a serious allegation which could have very long term consequences. If you have not hired a lawyer for the first setting, then you will have an opportunity to advise the court that you are in the process of getting an attorney, and you need to get one.
To add to the previous answer, Assault in which a male is accused of assaulting a female, is also a crime involving moral turpitude. It has many consequences which are not obvious and are very far reaching, much like Attorney Henley mentioned, that it cannot be non-disclosed even after completion of deferred adjudication. It can also effect gun-ownership rights. And, as previously mentioned, can be used in the future to enhance other accusations.
Depending on if this is a class c misdemeanor or a class a misdemeanor (or higher) completely changes the possible outcomes you may be facing. Good luck and I wish you the best. I would strongly recommend contacting a lawyer to help you make the best of this situation.