It is unclear from your question whether you are a juvenile or an adult.
If you are a juvenile, then there is a statute (RCW 13.40.070 - see link below) which sets out the criteria for diversion. The statute states generally that Class A felonies, Class B felonies, and some Class C felonies are not eligible for diversion (see the statute for specifics). Even if your charge is eligible for diversion, the prosecutor still has discretion to decide whether or not to send the case to diversion. The decision would be made before the charge is even filed (it is an agreement that is entered into in lieu of prosecution).
If you are an adult, then it is basically up to the prosecutor. The biggest factor will be the seriousness of the crime with which you are charged. I have seen many simple drug possession cases go through the diversion program. By contrast, a prosecutor would rarely consider diverting a serious or violent felony. This would generally be decided after the arraignment.
You must talk to an attorney! Any felony is extremely serious and you should explore all legal defenses available to you. There many attorneys, like me, who offer free consultations. Talk to somebody in person who can give you a fully informed opinion.