I couldn't agree with you more that it is unfair to dismiss your complaint - it should really be the decision of your daughter/you. And I am not saying that it would be worse for your daughter to keep on top of it, victims need justice and blowing that off can also be detrimental in so many ways - only something to be considered if it goes on for years.
Also, yes, a years difference is not relevant to 'victimhood.' A big strong 16 year old can certainly do damage to a 17 year old.
"if the district court dismissed our complaint because the attacker was a juvenile, then was juvenile court supposed to hear my daughter because as they say she is not a juvenile?"
According to the Mass. bar, juvenile courts have jurisdiction over delinquent complaints concerning children between the ages of seven and 17 who are accused of violating city ordinances, town by-laws or state statutes. So it is unclear to me why they are not addressing this, since your daughter is only 17. So I have no clue why the magistrate is not taking hold of this one - I suspect he just doesn't want another case on his docket and so is saying, (wrongly) "hey, it is one kid against another, they both should just shut up and go away." I don't agree at all, just as I wouldn't agree if it were adults, unless of course the adults agreed.
Without an adjudication of delinquency, the court is not going to render opinions on who was the victim and who was the aggressor, so I don't want you holding your breath for unofficial statements - they would potentially be putting themselves into hot water.
Since I don't know the court's docket load, it is not clear if they court is dragging this out until 6/9 or if that is the set date for a hearing, but I do agree that if you want charges filed, that should be done.
However, you are confused as to why the magistrate doesn't know that your daughter is the victim and the other is the aggressor, you have to remember, he has not tried the case yet? There is no way he can know that. All he knows is that delinquency findings, if it ends up being believed what the 16 year old is saying and/or other evidence or witnesses support her, then your daughter could get in some trouble - perhaps he doesn't want you to risk her freedom like that over this. I am sure he is very used to parents who all think their child is blameless - yet most are not. He has no way to knwo that your daughter is the exception, when he hasn't yet even had the opportunity to try the case.
The real question is, are you going to push to have charges pressed against the 16 year old.
"This could have all been over that day if he would just have considered the evidence, I mean wasn't he supposed to consider it?"
The day you sought to file the complaint would NOT be the day he considers the evidence - notice has to be given, an opportunity to get discovery (by both sides), etc.
"(Does that mean I will have accepted it twice and therefore owe two payments? I just want to be clear and fair.) "
No, as of now, as per my screen, you have 'deposited' but not accepted (whichh is understandable, as you were unclear, or rather I was unclear, and you needed clarification). YOu can accept 1 or more answers, but know that each answer accepted will be charged, so if you only want to pay for the value of 1 answer, only click the ACCEPT button on one of them.
Let me know if you have further questions. And I wish you the best with this! Remember, if you don't get resolution adequately, consider filing civilly, even with self-represenation -if nothing else, it will be a pain in that girl's rear and perhaps make her parents think twice about not trying to resolve amicably.