Please understand that there is no such thing as anonymity on the web. We may choose to blog under a pseudonym and to have a "private" blog but that does not make us "anonymous". We all leave digital footprints and they are quite easily followed. If you have a "private" blog and one of the official user that you allow to read your blog, and they quote your poetry in their public blog and/or choose to link to it in your private blog, or refer to it anywhere on the internet, then it will be available on the internet. If you use an RSS widget on your blog then your posts will be available as well.
These are the privacy options we can choose from:
video > http://wordpress.tv/2009/01/14/setting-your-posts-or-entire-blog-to-private/
Note that the most "private" of all is this one "I would like my blog to be visible only to users I choose". It's not the setting you have chosen. I can read your blog.
Provided you choose that ^ setting #3. and do NOT tell anyone at all your blog exists, and you do NOT create official users, and you do not post an RSS feed, and you never ever share the URL of that blog anywhere then you will have done the most you can do.