You're facing a charge that is a "wobbler" in California, meaning it can be charged as either a felony (max of 3 years in state prison) or a misdemeanor (max of 1 year in county jail).
Essentially, they're saying you used threats or force to try and get an "executive officer" (which can include police officers) not to do his job. It's often times referred to as resisting arrest by with additional force.
What would I suggest? Getting a good criminal defense attorney to represent you. Prosecutors tend to take assaults on officers seriously and will want to see you punished. Your attorney can fight against the charges and/or protect your rights.
Meanwhile, don't make any statements about this to anyone except your attorney in a confidential setting.
I agree with Mr. Dane and make sure you get a good criminal defense attorney to assist you. It is unclear if you are being charged with the felony or the misdemeanor. In either event an attorney will be needed due to the nature of the offense.
Penal Code Section 69 is a large grab bag that prohibits multiple acts involving resisting or deterring a peace officer in the performance of their dutis. It can be punished either as a felony or misdemeanor. The District Attorney will decide how and what to file. There is no way to tell what exactly you are facing until the final resolution of the case. Everything depends upon the exact circumstances. If you can afford an attorney, you should hire one, if you can't, you should seek the services of the public defender.