Always double space and use a non-proportional font when using a word processor. Courier 12pt is the standard. Your first page should look like this. Pen names are generally considered affectations and a sign of the amateur. Round your word count to the nearest 100.
Word count deserves a few moments of our time.
There are as many ways of counting how many 'words' your story is as there are writers. I recommend the following formula, something that an editor friend of mine likes. That will give you a number of 'words' per line. If you are following instructions, that will be 26 or 27 since you double spaced your manuscript. Your first page will be 13 because it's only half a page.