i just got charged with a d fenoly and assult and it my frist offence

Without knowing more about your specific charges and the strength of the evidence (both inculpatory and exculpatory) it is impossible to say with any degree of certainty what is likely to happen with these charges.  The way the criminal justice system works is that once an individual is arrested, a prosecutor will review the evidence (provided by the police) that demonstrates that a person is guilty.  If the evidence is weak, or if a defense attorney is able to convince the prosecutor that you are not likely to be convicted of the crimes (for example if there is a valid defense or if there is strong exculpatory evidence) then the prosecutor will be more likely to drop the charges.  If the opposite is true, and/or if there are aggravating factors present (such as a victim who wishes to see you prosecuted) the prosecutor will be less likely to resolve the charges favorably.  Nevertheless, whenever you are charged with a felony it is a serious matter; therefore, I suggest that you consult with and/or retain a skilled criminal defense attorney as soon as possible in the interest of obtaining the best possible resolution of your charges.