There are statutes of limitations on the criminal side, as well as the civil aspects of this type of case. From the Domestic Violence Standpoint these laws were written to be used fairly quickly. The farther away in time from the incident causing you to seek protection the less likely a protection order will be granted. The Code allows for you to discuss past incidents of violence, so stuff from some time ago can be used to bolster your request, but not the specific request. From a Civil Litigation standpoint (personal injury lawsuit) the typical time to file a claim would be 1 year from the date of the incident. I'm not positive on the criminal statute, as I don't practice in that area. Depending upon the type of filing you intend to pursue (action for protection under DV Laws, action for monetary damages under personal injury laws, or action for incarceration for criminal violations) the answer to your question is different.
If you want to sue someone civilly who has assaulted you, you need to speak with a ;lawyer who works in that area. I suggest you find a personal injury lawyer in your area and ask them this question. They will, I am certain, answer it for free.
The following response pertains to timing of civil actions, only:
Code of Civil Procedure section 335.1 proscribes a two-year limitations period for civil assault or battery actions that occurred after January 1, 2003. (Prior to that date, the limitations period was only one-year.)
Code of Civil Procedure section 340.15 governs the limitations period pertaining to domestic violence. The domestic violence limitations period is three-years. The period begins to run at the time of the last act of violence, thus allowing a person who files a timely suit to recover damages for continuous abuse during a marriage.
Notwithstanding the above, it is in your best interest to file a civil action earlier, rather than later. This allows for more accurate recollection of events and may also bear on availability of evidence and witnesses.
If you seek ihformation regarding criminal statutes of limitations, you should check with a either CA criminal attorney or your local law enforcement office.