When you’re building your website, put some thought into what you want your administrative username to be. Some tips:
1. NEVER use “admin” as the username. The bulk of the hacking attempts I see try to use “admin” to get into my websites.
2. Don’t use your website name, either. That seems to be the second most popular choice.
3. Don’t use your name. On this website, that’s the third most popular choice.
Choose something that’s meaningful to you, but not necessarily well known. You can always choose a nickname here on WordPress that is more accurate if you use WordPress as a blog and allow your posts to display names.