My CCW instructor and SD training pros I've been with and studied all agree. The less you say the better. Brief statement, never say the word "kill". Use words like imminent, fear, threatening, etc,.. Make YOUR statement sound like a LEO and then shut up.
Saying " I shot and killed the bastard " is no good. You need the lingo to be more refined. Prepare for a full blown investigation regardless, and in today's world have a good knowledgeable lawyer.