From Ayoob again, if involved in a self-defense shooting:

Step One: Establish The Active Dynamic
The justice system tends to see the man who got hurt or the one who made the initial complaint as the victim, and the person who inflicted that harm or the one complained about as the perpetrator. The man who tried to murder you is now lying in a puddle of blood looking very much like a victim. You, with your smoking gun, look a lot like a perpetrator. It is therefore imperative that you establish from the beginning that he is the one who tried to violently victimize you. It is vital that you call 911 immediately, give your location and tell them that you’ve been attacked and that the perpetrator is down.

and the last:
Step Five: Offer Full Cooperation After Speaking With Counsel
There are many reasons experts recommend against participating in a detailed interrogation in the immediate aftermath of a near-death experience, when you are most likely shaken. For one thing, investigators will ask questions as they occur to them, and their notes later will create the false sense of you narrating events in that sequence, which is likely not the actual sequence. In “answer the question” mode, if the right questions aren’t asked, your failure to mention certain things can be seen later in court as “he must have made that up later.” Police are advised by their unions not to go into great detail in the immediate wake of such crises. Get the important points across at the scene—“He attacked me. His accomplice got away, but here’s his description.” The rest can wait until later. Various experts recommend 24, 48 or even 72 hours to get your recollections in order. The authoritative Force Science Institute recommends at least one full sleep cycle before submitting to detailed interrogation.

Have to tell a story: acquaintance was a cop for many years.  There was a messy shooting at a pharmacy, and in the end- due to the last thing he did- the pharmacist wound up being charged and convicted for homicide.  Cop mentioned at one point "Y'know, if he'd just shut up and let his lawyer do the talking, he'd probably never even have been charged."