She is not going to trial, trials are to determine guilt and items that are in dispute. She has already admitted guilt. They may have set a hearing to determine whether or not she violated probation however there will be no jury for that hearing.
Your daughter should hire a lawyer because he or she can often smooth things out and in the meantime try to do some, even if it is only a few hours of community service she should try to get some done.
If she was sentenced to community service she will need to complete it. She probably didn't complete it before her next hearing date. Therefore, she should just get the Public Defender and if this is her first time not completing the hours required the judge may give her some leeway and order an extension. Questions to ask are (1) does she go to school? (2) does she work? (3) does she have kids? these are called angel statistics (they are used to soften the irresponsibility of the defendant and to give fire power to an extension)