No one here can tell you what the likely outcome may be because we haven’t seen and heard whatever evidence will be presented in court. Moreover, these boards relate to U.S. law and it’s unlikely that any Canadian lawyers will see and respond to your question. The basic problem in mutual combat where the only evidence is the conflicting stories of the persons involved is figuring out which of them is truthful and which of them are not. If the court believes her accusers, she might well be convicted.
How it will affect her if convicted depends on Canadian law and how the case plays out. In the U.S. a 17 year old would be prosecuted for this in juvenile court in many states with the result that the record of the case would be sealed at either age 18 or 21. Thus, the record would not be publicly available and wouldn't follow her around for years to come like adult convictions do. I do not know whether Canada follows a similar practice, though I suspect it does something similar.