Is someone trying to hack my blog?

Hello, I don’t know if WordPress has a tracker – would be great if they did – but I’m using xtreme tracker, and from the log on my regular site, I see that a reader did something I’ve never seen before: he typed mysite.com/park_blog/author/admin/ .

Up came my name as listed on my profile and a list of all my posts. I don’t have much on my profile, or more would have come up.

Is this ok? How did he know to type this, the part adding author and admin? Can he get into my blog through a backdoor? I tried to change my username from admin in my profile, but it says it isn’t editable. Thank you for ideas.