Criminal offence

Yes but does she know an adult can make the bullying stop? Can you make the bullying stop? What levererage do you have over the bully if the school isn't prepaied to act against them? Either you act against the bully yourself (could become a police matter) or withdraw your daughter from the school. If the school won't act what options do you have? No number of teacher parent meetings will help if the school isn't willing (or can't be made) to act to stop the bullying.

I knew a girl once. Her younger sister was being bullied. She she went to the toughest meanest kid in her sisters school and said 'I will pay you money to threten the bully to leave my sister alone and to generally keep an eye on my sister to make sure she's fine.' Aparently this worked quite well. I'm not sugesting you do this ... but I am saying action that doesn't reley on the schools cooperation may be needed.

If this were my daughter, I'd be quizzing her as deeply as I know how to establish her state of mind.

Did she carry the knife to school to deter aggression? Did she have an actual plan? OR was it more of a half arsed " I gotta do something move". 

You really DO need to understand as her friend rather than as her parent why she did that thing. Use your partner to obtain a second opinion, encourage honesty, (even if it is not what you want to hear, stifle any negative reaction you have) as knowing the truth of the matter is most important.

You also need to work through all the possible scenarios for her / with her and get her to try and find the winning way of playing the "knife to school game" as an intellectual excercise.

Point out to her that now she has been NOTICED more than ever, was it really such a smart move? 

She's clearly trying to solve a very difficult problem using 13 year old brains, and what she could really use is help actively working the problem. 

I did not have that advantage when I was her age and was being ruthlessly bullied at school, indeed my home life was worse, so in fact I went the "psychotic violence as a deterrent" route between 8 and 11 until someone finally broke my nose, and I realised it was no deterrent, and worse I was in strife with teachers and seeing psychologists etc. none of which did I want to be involved in, so I switched from violence to psychology and avoidance of conflict strategies, which whilst they didn't make me feel much better about being generally persona non grata did win me a lot more peace and quiet, and time to do things "better" than fighting or trying to get along with people who had no time for me. 

Although being a bloke I did get occasionally "forced" into a fight, which I generally lost, and by the time I was sixteen I identified strongly as a "coward" unless I really had to physically defend myself, in which case I'd pick whatever tool, strategy or tactics I needed to make sure I was going to win and advance upon my opponent fully intent and focussed  on doing them an adequate level of harm. Those I always won.

By the time I reached my early twenties my coping skills and basic psychology was sufficient to avoid physical altercations altogether and apart for a couple of incidents involving loons & a mugging attempt all of which were dealt with by "managing the situation better than my would-be opponent".

She might as well accept that this is her burden, and finding ways to cope that do not involve harming or threatening to harm others is indeed the pinnacle of skill and she can use her autistic detachment plus learning skills to learn how to deal with others using psychology rather than cold steel. 

The support I got when I was being bullied, was "Find the biggest one, and smash him to the ground then look at the others and ask, Who's next?"

Whereas the correct advice would have been more along the lines of: "Go straight to the school office next time it happens and request an interview with the deputy head. Explain as calmly as you can what is being done to you that you do not like or makes you feel sad and unwanted, and make a point of giving them my mobile phone number and ask them to call me as soon after the interview as is convenient..." IF anyone calls you a "snitch" etc, calmly point out that if they don't want the trouble, ten just leave me alone, because if asking for help is what it takes to get them off your back, that is what you will do. Most importantly of fall make sure she reports any actual threats made against her to the same person immediately. Bullies fear "authority" more than anything else. 

That's my take on it FWIW, and it took me a LOT of effort to find a path that worked for me and those inevitable jerks you meet who, no matter how you try, will NOT like the cut of your jib.

But whatever you do, she needs to see the circular nature of violence, and she needs to know to NEVER pick up a deadly weapon unless she is fully committed to using it to kill someone. Killing someone because they "make you unhappy" is of course madness, so she needs to rule that out and find other solutions that will actually work. I'm living proof that those alternative solutions work, but she needs help working the alternatives out if her suffering is to be cut shorter.   

I've made assumptions based on your testimony, and I am optimistic that your daughter just made a dumb move, but she needs to know that people will want to interview her a lot for a while, and that she should just co-operate and tell the truth at all times in such interviews that may happen in order to make them leave her alone.

I'd definitely want my most legally competent person I could get my hands on to get their hands up the police sharpish and ask WHY they have charged your 13yr old  daughter... 

I hope my admittedly over informed and perhaps "alternative" take on the matter helps in some small way.

I tried very hard to use the right words to convey the meaning and nuances as best as I can.  

Well yeah she has me and I'm on that phone or down at the school slot actually.. she took a knife she wouldn't have used it. She is quiet and struggles with dealing with emotions. Yeah she regretted it and didn't fully understand that effect this would have.Shr has been punished by school and charged by the police. But yeah maybe I'll get the support since no one listens. I have 2 older boys on spectrum and this is different. I make my daughter number 1 priority so don't assume. 

yes but also true. Children who think the adults around them can and will protect them don't generally carry knives. At least not for protection. Parents, teachers, the police themselves, there is plenty of blame to go around. Lets not forget physical bullying is assult. There is nothing to say you can't arest a 13 year old for a playground punch up. In some cases actually that might be best. A night in the cells might be the shock needed to deter future bulying.

Knowing something about knife crime I can tell you kids that take knives with them are usually scared of being physically hurt themselves not premeditating an attack themselves, so they go overboard in the way they feel they have to defend themselves. You have to get to the bottom of why she had a knife in the first place it could be important to how she gets charged and if it goes to court. And if the School is harbouring physically violent bullies that promote kids feeling unsafe enough to have knives they need to take it seriously and crack down on the bullying, the cause of it, not the symptom.

Peter said:

If carrying the knife is related to the bullying she wouldn’t of done it if she thought she could rely on you in the first place.

Isn't that a bit harsh?

I don’t know the situations specifics. But two possibilities spring to mind.

One she just likes knives saw a knife but she thought was cool and wanted to show it off to people. Autistic people can get Fixated on anything could be our favourite football, rubber ducks, or a knife. And I dare say in her mind a knife  is a tool not a weapon and why wouldn’t you show a tool that you really like to your friends. she’d  probably carry a cool spanner in a pocket to show people as well and and from her point of view why would anyone consider that to be a problem? 

possibility 2 she’s being bullied. I mean physically assaulted repeatedly on a regular basis. and with her social issues she cannot tell the difference between someone just being angry enough to punch her and wanting to kill her. and potentially having gone to parents or teachers repeatedly talking about how she’s being bullied and having nothing done about it she has become so frightened that she feels she needs to carry a weapon and resolve the bullying issue with force on her own because no one else will step in on her behalf. And of course if you then turn around and tell her off for this to her you look like a hypocrite because you did nothing about the bullying.

autistic people tend to think in a straight line. if someone uses physical force against you you use physical force back against them. even if that’s not socially acceptable. especially if the socially acceptable route isn’t yielding results. and if you have say maybe 4 bullies who like to gang up on you you need a way to multiply your force four times.

so of course she isn’t going to incriminate herself to you by discussing her real motivations or feelings. What would you do if she did? Would you walk into the school yard and give her bullies a clip round the ear? Would you pull her out of school and homeschool her to keep her away from them? Anything that might improve the situation from her point of view? If carrying the knife is related to the bullying she wouldn’t of done it if she thought she could rely on you in the first place.

Just bumping back up.