As you are now aware, threatening is considered a crime, and you can be prosecuted for it regardless of whether or not the alleged "threat" resulted from a mutual agreement.  If you were arrested after you went down to the precinct to "discuss" the matter, chances are that you said or signed something that can be considered incriminating.  Depending on the degree of the charge, it is certainly possible that, if convicted, you could be sentenced to a period of incarceration.  However, from procedural perspective, it is not clear that just because the prosecution said that they are "ready" to go to trial that the matter actually will go to trial.  Nevertheless, given the potential consequences of a conviction I strongly suggest you consult with and/or retain an experienced criminal defense attorney in the interest of obtaining the best possible resolution of this matter.