Is a birth plan necessary?

Im a ftm and I’ve just sort of been going with the flow. I haven’t take any classes or anything like that. I keep up with what’s going on by weeks. However, I’m due here in a few weeks and wanted to pack my bag and one of the things it says the ask for is your birth plan? Did you like print one out? Did you even need one? If you did, what did it look like? If you didn’t, why not?