It is very important, but it can wait. My first cut at any new piece of software has a bunch of names containing words like "stuff" and "thing". I find it's ok to go back and rename things later if it helps you remain in the flow state of just getting your ideas down in writing.
Oh definitely. My wife took a bunch of creative writing classes recently, and one of the biggest things she took away from them is that there is no "right way" to write a book. I'm pretty sure the same is true of writing computer programs!
