Quite often, Texas schools are punishing what was once a violation of school rules with criminal charges. Ironically, if your daughter was charged with a Class A assault, she would have had more protections in terms of her identity and potential criminal record than as it stands, with her charged with a Class C (JP Courts handle only Class Cs; I would guess she's been charged with Disorderly Conduct - Fighting). If she is found guilty, she will have this charge on her record for the rest of her life even though this occurred when she was 12.
If your daughter is innocent, she should not plead guilty. What many JP and Municipal courts try to convince people to do is to plead no contest and accept what is called deferred disposition. If your daughter pays some court costs, does some community service, and is not re-arrested during a period of up to 6 months, the case will be dismissed and she will then be eligible to expunge her arrest record (but you would have to hire an attorney or file that petition yourself). That deal is not always open, but the guaranteed result is worth it to some people even if they are factually innocent of the charge.
Your daughter has the right to a jury trial (which I would strongly recommend in JP or municipal court), but because these courts treat juvenile defendants like adult ones, the court likely does not believe she is entitled to a court-appointed attorney (if you financially qualified), so if you want legal representation, you will have to pay for it yourself. (You may want to ask the court to appoint your daughter an attorney, reminding the court that this could stay on her record for the rest of her life and that if she had been charged as a juvenile she would absolutely be entitled to one.). Otherwise, I would recommend you speak with local criminal defense attorneys who regularly take cases to trial about your daughter's case.
Disclaimer: This answer is provided as a public service and as a general response to a general question, it is not meant, and should not be relied upon as specific legal advice, nor does it create an attorney-client relationship.
